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92 Sc400 Will Not Start


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Can anyone please help me with this? The lexus dealer here will not work on this car, and I really don't trust anyone else to do any work on it. PLEASSSSSSSSSSSSSSSSSSSSSSSSSSSSSSE!

Hello, I have a 92 Sc400. I have only had it 3 weeks so I am still getting to know it. PROBLEM, got in it the other day and it would not start, cranked but did not turn over. Changed the plugs. Ran the diagnostic, it showed the TPS sensor, so I changed both the main and sub throttle. Now it will crank and turn over but died immediatly, in a hail of white fumes. Ran the diagnostic again, now shows MAF sensor or circuit, so I changed that out with a used but tested good one. Still nothing. Ran the diagnostic again and all it does is blink none stop, no codes just blinking. So I had it towed to a shop he had it for a few days, said it needed a new timing belt and tensioner, But the guy I bought this from had put a new timing belt water pump and tensior on only 2 months before. The car has 219,000 on it. I have also ordered a new fuel pump that sould be here in a couple of days, Any help would be great.

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Hello, I have a 92 Sc400. I have only had it 3 weeks so I am still getting to know it. PROBLEM, got in it the other day and it would not start, cranked but did not turn over. Changed the plugs. Ran the diagnostic, it showed the TPS sensor, so I changed both the main and sub throttle. Now it will crank and turn over but died immediatly, in a hail of white fumes. Ran the diagnostic again, now shows MAF sensor or circuit, so I changed that out with a used but tested good one. Still nothing. Ran the diagnostic again and all it does is blink none stop, no codes just blinking. So I had it towed to a shop he had it for a few days, said it needed a new timing belt and tensioner, But the guy I bought this from had put a new timing belt water pump and tensior on only 2 months before. The car has 219,000 on it. I have also ordered a new fuel pump that sould be here in a couple of days, Any help would be great.

Well I changed the fuel pump out, along with the fuel filter which by the way was a factory original. So I had to fabricate a little to get a new one on. It still will not run. So I had it towed to a lexus dealer. Hopefully it won't cost to much.

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Hello, I have a 92 Sc400. I have only had it 3 weeks so I am still getting to know it. PROBLEM, got in it the other day and it would not start, cranked but did not turn over. Changed the plugs. Ran the diagnostic, it showed the TPS sensor, so I changed both the main and sub throttle. Now it will crank and turn over but died immediatly, in a hail of white fumes. Ran the diagnostic again, now shows MAF sensor or circuit, so I changed that out with a used but tested good one. Still nothing. Ran the diagnostic again and all it does is blink none stop, no codes just blinking. So I had it towed to a shop he had it for a few days, said it needed a new timing belt and tensioner, But the guy I bought this from had put a new timing belt water pump and tensior on only 2 months before. The car has 219,000 on it. I have also ordered a new fuel pump that sould be here in a couple of days, Any help would be great.

Well I changed the fuel pump out, along with the fuel filter which by the way was a factory original. So I had to fabricate a little to get a new one on. It still will not run. So I had it towed to a lexus dealer. Hopefully it won't cost to much.

Well I got an answer to my problem. It was the fuel pump. But, Upon further review I Bought an oem fuel pump Installed it with the factory harness and it fired right up. Well not right up but it started. I let it idle for about 15 minutes and then it died but it started right back up. I drove it for about 3 miles and could not keep it running in drive while stopped. I know there is a vaccum leak somewhere but have not found it yet. I also replaced te EFI relay. That was yesterday. Today it is doing the same thing it did before I put the new pump in, just cranks and cranks. the diagnostic says RPM sensor. Has anyone ever had a problem like this? Has anyone ever had a problem in the way they park a vehicle like on an inclined driveway. Pleassssssssssse somebody HELP??

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Hello, I have a 92 Sc400. I have only had it 3 weeks so I am still getting to know it. PROBLEM, got in it the other day and it would not start, cranked but did not turn over. Changed the plugs. Ran the diagnostic, it showed the TPS sensor, so I changed both the main and sub throttle. Now it will crank and turn over but died immediatly, in a hail of white fumes. Ran the diagnostic again, now shows MAF sensor or circuit, so I changed that out with a used but tested good one. Still nothing. Ran the diagnostic again and all it does is blink none stop, no codes just blinking. So I had it towed to a shop he had it for a few days, said it needed a new timing belt and tensioner, But the guy I bought this from had put a new timing belt water pump and tensior on only 2 months before. The car has 219,000 on it. I have also ordered a new fuel pump that sould be here in a couple of days, Any help would be great.

Well I changed the fuel pump out, along with the fuel filter which by the way was a factory original. So I had to fabricate a little to get a new one on. It still will not run. So I had it towed to a lexus dealer. Hopefully it won't cost to much.

Well I got an answer to my problem. It was the fuel pump. But, Upon further review I Bought an oem fuel pump Installed it with the factory harness and it fired right up. Well not right up but it started. I let it idle for about 15 minutes and then it died but it started right back up. I drove it for about 3 miles and could not keep it running in drive while stopped. I know there is a vaccum leak somewhere but have not found it yet. I also replaced te EFI relay. That was yesterday. Today it is doing the same thing it did before I put the new pump in, just cranks and cranks. the diagnostic says RPM sensor. Has anyone ever had a problem like this? Has anyone ever had a problem in the way they park a vehicle like on an inclined driveway. Pleassssssssssse somebody HELP??

Tonyw,

Did you ever find the fix for your SC?

I also ran into the same problem today. Got in and tried to start the car. It cranks but no ignition. I park on a slight incline. I opened up the gas tank filler cap, and found fuel pushing up to the top of the filler neck. Anyone have any ideas what is the problem. It has been super hot these past few days in N. Calif. Fuel ECU? Ign Coil? Please! I need help.

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Well, I am replying to myself. After reading the posts, I swapped out the relays in the fuse box under the hood (between the EFI and the defrost) and the car started right up. I tried starting the eng before switching out the relays and the car wouldn't start, so I know this fixed it. The funny thing is, I swapped the relays back, and the car still started right up! Anyone have any ideas on this phenomenon??? Again, I hardly drive the SC, and it's been extremely hot this past couple days in Northern CA.

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Well, I am replying to myself. After reading the posts, I swapped out the relays in the fuse box under the hood (between the EFI and the defrost) and the car started right up. I tried starting the eng before switching out the relays and the car wouldn't start, so I know this fixed it. The funny thing is, I swapped the relays back, and the car still started right up! Anyone have any ideas on this phenomenon??? Again, I hardly drive the SC, and it's been extremely hot this past couple days in Northern CA.

yes your car was in limp in mode and when you took out the relay it reset the ecu

wouldnt be suprised if it happens again

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Well, I am replying to myself. After reading the posts, I swapped out the relays in the fuse box under the hood (between the EFI and the defrost) and the car started right up. I tried starting the eng before switching out the relays and the car wouldn't start, so I know this fixed it. The funny thing is, I swapped the relays back, and the car still started right up! Anyone have any ideas on this phenomenon??? Again, I hardly drive the SC, and it's been extremely hot this past couple days in Northern CA.

yes your car was in limp in mode and when you took out the relay it reset the ecu

wouldnt be suprised if it happens again

So is my ECU bad? Should I replace it before "pulling out the relay fix" fails to reset the ECU anymore? Just confirming you mean Fuell pump ECU that is behind the right passenger panel area. Thanks for replying.

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can you get any engine codes?

it may be a sensor that was going bad,

has completly failed.

making your car stay in fail mode"Limp in mode"

my car is doing this, it wont give me a code when its in limp mode

but before it goes in limp mode it will through code 55

which is rear kcnock sensor

replaced it, no change

checked all wiring and there is no shorts or damage

so i am awaiting a used ecu now.

so it could be your ecu also.

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can you get any engine codes?

it may be a sensor that was going bad,

has completly failed.

making your car stay in fail mode"Limp in mode"

my car is doing this, it wont give me a code when its in limp mode

but before it goes in limp mode it will through code 55

which is rear kcnock sensor

replaced it, no change

checked all wiring and there is no shorts or damage

so i am awaiting a used ecu now.

so it could be your ecu also.

Well I finally gave in and had it towed back to Lexus, its there right now. they say its not getting spark, but everything under the hood checked out ok. so they are going to do an ecu and wiring test tommorrow. And i hope they will have a definite answer for me. they also suggested i plug the fuel pump ecu back in. i never checked the fuel filer line to see if fuel was backing up in it. i also changed the efi sensor with no luck.

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I haven't checked any codes because I don't own an OBD reader. The car has been starting ok, the first start takes a little longer. Once I get it going, it restarts like it used to. It seems like the car throws out erroneus fault codes from what I am gathering from the comments posted. The parts aren't cheap. I don't mind buying a replacement part for the car if I know it will fix the start problem. I hope you guys are able to diagnose the problem and get a permanent fix. Please keep sharing your knowledge. It is very much appreciated, bro!

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I haven't checked any codes because I don't own an OBD reader. The car has been starting ok, the first start takes a little longer. Once I get it going, it restarts like it used to. It seems like the car throws out erroneus fault codes from what I am gathering from the comments posted. The parts aren't cheap. I don't mind buying a replacement part for the car if I know it will fix the start problem. I hope you guys are able to diagnose the problem and get a permanent fix. Please keep sharing your knowledge. It is very much appreciated, bro!

I still have mine at the dealer, they ran a full wire test all the way to the ecu and the ecu is bad, so I bought a remand one for $295 and had it shipped to the dealer, just waiting on the dealer to install. And tat will be the end of it. When I bought the car I thought it would be something good to fix up and resell. Now I think it will be something to just sell. It has been nothing but a giant pain in the !Removed!. I will never recommend this car to anyone.

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I haven't checked any codes because I don't own an OBD reader. The car has been starting ok, the first start takes a little longer. Once I get it going, it restarts like it used to. It seems like the car throws out erroneus fault codes from what I am gathering from the comments posted. The parts aren't cheap. I don't mind buying a replacement part for the car if I know it will fix the start problem. I hope you guys are able to diagnose the problem and get a permanent fix. Please keep sharing your knowledge. It is very much appreciated, bro!

you check thye codes by jumping e1 and te1 on either diagnostic port

turn key on count the flashes

I still have mine at the dealer, they ran a full wire test all the way to the ecu and the ecu is bad, so I bought a remand one for $295 and had it shipped to the dealer, just waiting on the dealer to install. And tat will be the end of it. When I bought the car I thought it would be something good to fix up and resell. Now I think it will be something to just sell. It has been nothing but a giant pain in the !Removed!. I will never recommend this car to anyone.

just wait till the ecu is right

the ecu controls everything ..almost

put my new ect/ecu tonight and was amazed!!!!!

the whole car came alive and fast as ever

no wierd stuff happening.

and for only 75 bucks

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I haven't checked any codes because I don't own an OBD reader. The car has been starting ok, the first start takes a little longer. Once I get it going, it restarts like it used to. It seems like the car throws out erroneus fault codes from what I am gathering from the comments posted. The parts aren't cheap. I don't mind buying a replacement part for the car if I know it will fix the start problem. I hope you guys are able to diagnose the problem and get a permanent fix. Please keep sharing your knowledge. It is very much appreciated, bro!

you check thye codes by jumping e1 and te1 on either diagnostic port

turn key on count the flashes

I still have mine at the dealer, they ran a full wire test all the way to the ecu and the ecu is bad, so I bought a remand one for $295 and had it shipped to the dealer, just waiting on the dealer to install. And tat will be the end of it. When I bought the car I thought it would be something good to fix up and resell. Now I think it will be something to just sell. It has been nothing but a giant pain in the !Removed!. I will never recommend this car to anyone.

just wait till the ecu is right

the ecu controls everything ..almost

put my new ect/ecu tonight and was amazed!!!!!

the whole car came alive and fast as ever

no wierd stuff happening.

and for only 75 bucks

Are you talking about the fuel ECU, or the engine ECU? Only 60 buck? Where did you get it? Is this ECU the one behind the right rear passenger seat side panel? Thanks in advance.

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Well, I am replying to myself. After reading the posts, I swapped out the relays in the fuse box under the hood (between the EFI and the defrost) and the car started right up. I tried starting the eng before switching out the relays and the car wouldn't start, so I know this fixed it. The funny thing is, I swapped the relays back, and the car still started right up! Anyone have any ideas on this phenomenon??? Again, I hardly drive the SC, and it's been extremely hot this past couple days in Northern CA.

yes your car was in limp in mode and when you took out the relay it reset the ecu

wouldnt be suprised if it happens again

Yup, it happened several more times. Now resetting the relay won't fix the problem. I took off the left rear passenger side panel to access the Fuel ECU and took off the connector and reset it, and the car started fine again. I ordered a new fuel ECU from Park Plano Lexus Dealer in TX. Hopefully the new fuel ECU will solve my start problems.

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  • 2 weeks later...

Well I replaced the fuel ECU with a new one, and it hasn't failed me yet when I start the car these past two days. I'm keeping my fingers crossed that the old fuel ECU was bad. I also changed out the battery terminals due to corrosion. Does anyone have any ideas what is the best "lube" to put on battery terminals to keep the corrosion away? How about just plain old petroleum jelly?

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Well I replaced the fuel ECU with a new one, and it hasn't failed me yet when I start the car these past two days. I'm keeping my fingers crossed that the old fuel ECU was bad. I also changed out the battery terminals due to corrosion. Does anyone have any ideas what is the best "lube" to put on battery terminals to keep the corrosion away? How about just plain old petroleum jelly?

Don't put anything on the posts. Buildup on the posts usually indicates some overcharging. If you're getting slight corrosion, use a battery cleaning kit that consists of a circular wire brush for cleaning the inside of the terminals and a round post cleaner that works a bit like sandpaper.

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Well I replaced the fuel ECU with a new one, and it hasn't failed me yet when I start the car these past two days. I'm keeping my fingers crossed that the old fuel ECU was bad. I also changed out the battery terminals due to corrosion. Does anyone have any ideas what is the best "lube" to put on battery terminals to keep the corrosion away? How about just plain old petroleum jelly?

Don't put anything on the posts. Buildup on the posts usually indicates some overcharging. If you're getting slight corrosion, use a battery cleaning kit that consists of a circular wire brush for cleaning the inside of the terminals and a round post cleaner that works a bit like sandpaper.

Well I'm back with an update and it is not a good one. Bought the ECU and they shipped the wrong one. then I got the right one and the car started but died on impact, it did to the lexus guys what it did to me started then stopped, finally they got it to run for a few minutes but it died and the in remaned ECU was fryed. So I just said F**K it I am tired of messing with this thing. and I am going to start parting it out tommorow. So if you guys need any parts just let me know or go to EBay, my ID is tonyblue0

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Well I replaced the fuel ECU with a new one, and it hasn't failed me yet when I start the car these past two days. I'm keeping my fingers crossed that the old fuel ECU was bad. I also changed out the battery terminals due to corrosion. Does anyone have any ideas what is the best "lube" to put on battery terminals to keep the corrosion away? How about just plain old petroleum jelly?

Don't put anything on the posts. Buildup on the posts usually indicates some overcharging. If you're getting slight corrosion, use a battery cleaning kit that consists of a circular wire brush for cleaning the inside of the terminals and a round post cleaner that works a bit like sandpaper.

Thanks for the tip. I also just got the fuel filter replaced. I haven't had any problems every time I start the engine now. Keeping my fingers crossed.

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  • 3 weeks later...
Well, I am replying to myself. After reading the posts, I swapped out the relays in the fuse box under the hood (between the EFI and the defrost) and the car started right up. I tried starting the eng before switching out the relays and the car wouldn't start, so I know this fixed it. The funny thing is, I swapped the relays back, and the car still started right up! Anyone have any ideas on this phenomenon??? Again, I hardly drive the SC, and it's been extremely hot this past couple days in Northern CA.

yes your car was in limp in mode and when you took out the relay it reset the ecu

wouldnt be suprised if it happens again

Yup, it happened several more times. Now resetting the relay won't fix the problem. I took off the left rear passenger side panel to access the Fuel ECU and took off the connector and reset it, and the car started fine again. I ordered a new fuel ECU from Park Plano Lexus Dealer in TX. Hopefully the new fuel ECU will solve my start problems.

Hi there, :P

I am a newbie but had the very same problem and no code issues with a 92 LS 400. As it turns out we went through the same process of elimation and replacing of parts that you did. As it turns out the drivers side ignition coil was bad. The mechanic we used initally said because of the crank but no spark it was not getting fuel. After 2 months of dealing with this person and spending cost to $400 we had the car towed to a mechanic in Stockbridge, GA who works on nothing but LEXUS. It took him 30 minutes to find out what the problem was, it is now repaired with no problems. CHECK YOUR DRIVERS SIDE IGNITION COIL WHEN YOU HAVE CRANK BUT NO SPARK. Happy Driving. :D

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Well, I am replying to myself. After reading the posts, I swapped out the relays in the fuse box under the hood (between the EFI and the defrost) and the car started right up. I tried starting the eng before switching out the relays and the car wouldn't start, so I know this fixed it. The funny thing is, I swapped the relays back, and the car still started right up! Anyone have any ideas on this phenomenon??? Again, I hardly drive the SC, and it's been extremely hot this past couple days in Northern CA.

yes your car was in limp in mode and when you took out the relay it reset the ecu

wouldnt be suprised if it happens again

Yup, it happened several more times. Now resetting the relay won't fix the problem. I took off the left rear passenger side panel to access the Fuel ECU and took off the connector and reset it, and the car started fine again. I ordered a new fuel ECU from Park Plano Lexus Dealer in TX. Hopefully the new fuel ECU will solve my start problems.

Hi there, :P

I am a newbie but had the very same problem and no code issues with a 92 LS 400. As it turns out we went through the same process of elimation and replacing of parts that you did. As it turns out the drivers side ignition coil was bad. The mechanic we used initally said because of the crank but no spark it was not getting fuel. After 2 months of dealing with this person and spending cost to $400 we had the car towed to a mechanic in Stockbridge, GA who works on nothing but LEXUS. It took him 30 minutes to find out what the problem was, it is now repaired with no problems. CHECK YOUR DRIVERS SIDE IGNITION COIL WHEN YOU HAVE CRANK BUT NO SPARK. Happy Driving. :D

Thanks for the tip. When you said you had the very same problem and same process of elimination, just confirming you also swapped out the EFI relays, changed fuel ECU, replaced fuel filter, etc. Did your Lexus mechanic explain exactly why the driver's side ignition coil was the problem? Is it only the driver's side ign coil that is used for an initial cold start? Thanks for any info you can provide? And was your problem intermittent also?

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  • 1 month later...
I haven't checked any codes because I don't own an OBD reader. The car has been starting ok, the first start takes a little longer. Once I get it going, it restarts like it used to. It seems like the car throws out erroneus fault codes from what I am gathering from the comments posted. The parts aren't cheap. I don't mind buying a replacement part for the car if I know it will fix the start problem. I hope you guys are able to diagnose the problem and get a permanent fix. Please keep sharing your knowledge. It is very much appreciated, bro!

I still have mine at the dealer, they ran a full wire test all the way to the ecu and the ecu is bad, so I bought a remand one for $295 and had it shipped to the dealer, just waiting on the dealer to install. And tat will be the end of it. When I bought the car I thought it would be something good to fix up and resell. Now I think it will be something to just sell. It has been nothing but a giant pain in the !Removed!. I will never recommend this car to anyone.

Any news with your SC400?

I had a similar issue with the same car. The dealer said it was my engine ECU and solenoids. I took my car back from the dealer (waaay too expensive) and addressed both items but the problem persisted. My friend and mechanic gets a code saying I need an igniter. That was addressed as well as the fuel pump with no success. My mechanic says it may be related to the alarm having to get reset. Lexus says no. Now a friend mentioned a similar problem he was having and said it related directly to the throttle position sensor. This makes complete sense to me as the car can start but cannot maintain idle as if there is no fuel going to the engine.

I hope this points you to the right direction. Please let us know if this works for you.

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:angry: After the last 2 months of my car sitting. I put a fresh battery in it, changed the ignition coils, Ignitors, distributor rotors, camshaft sensors, main ECU (3), fuel pump ECU, a used EGR valve. with out the car turning over. SO I checked for spark using the plugs that are in the car and got nothing, so I put some old plugs in and it finally turns over, I only had 4 old plugs, so I went and got the oem plugs Autolite double platnium. The car cranks and turns over but dies immediatly. I am getting the code 71 egr valve.

Also the battery ground wire was getting very hot, so I checked that out and added an additional ground for it along with a new terminal.

As well as pulled the alternator and had it tested and it was fine. But the wiring harness was pretty messed up, with wires exposed, so I fixed those.

The other thing is when I used to crank on the engine it was a very distict high pitched cranking sound, ever since I changed the ignition coils the sound is very baritone. And when I am cranking on it every once in a while it will come back very strong sounding, then the battery dies out.

Anything, Anybody

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Well, I am replying to myself. After reading the posts, I swapped out the relays in the fuse box under the hood (between the EFI and the defrost) and the car started right up. I tried starting the eng before switching out the relays and the car wouldn't start, so I know this fixed it. The funny thing is, I swapped the relays back, and the car still started right up! Anyone have any ideas on this phenomenon??? Again, I hardly drive the SC, and it's been extremely hot this past couple days in Northern CA.

yes your car was in limp in mode and when you took out the relay it reset the ecu

wouldnt be suprised if it happens again

Yup, it happened several more times. Now resetting the relay won't fix the problem. I took off the left rear passenger side panel to access the Fuel ECU and took off the connector and reset it, and the car started fine again. I ordered a new fuel ECU from Park Plano Lexus Dealer in TX. Hopefully the new fuel ECU will solve my start problems.

Man an i was bitching about my fuel pump.... Im kinda lost lol now sounds like a job for the dealership!

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Well, I am replying to myself. After reading the posts, I swapped out the relays in the fuse box under the hood (between the EFI and the defrost) and the car started right up. I tried starting the eng before switching out the relays and the car wouldn't start, so I know this fixed it. The funny thing is, I swapped the relays back, and the car still started right up! Anyone have any ideas on this phenomenon??? Again, I hardly drive the SC, and it's been extremely hot this past couple days in Northern CA.

yes your car was in limp in mode and when you took out the relay it reset the ecu

wouldnt be suprised if it happens again

Yup, it happened several more times. Now resetting the relay won't fix the problem. I took off the left rear passenger side panel to access the Fuel ECU and took off the connector and reset it, and the car started fine again. I ordered a new fuel ECU from Park Plano Lexus Dealer in TX. Hopefully the new fuel ECU will solve my start problems.

Man an i was bitching about my fuel pump.... Im kinda lost lol now sounds like a job for the dealership!

been to the dealership they could not do anything. Just a bunch of overpayed oil changers.

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