baul79racer

Hello This is Paul with the '91 LS400 "Lost Power Story" Anyway....The fuel pump filter is located behind the back seat. It wasn't that complicated. The fuel pump was quiet as a snail.. and the filter from it was clean as nails. It's the size of cigarette box and basically it's a screen. Anyway. My Lex still looses power in the power brand range 4k - 6200 rpms. Once in awhile it get some power to 5k rpms with sluggish hick ups. I check the "cat" underneath the car it looks fine after running up a hill no signs of hot red glare. Tomorrow... I looking in on the fuel pressure regulator. Anyone think that's a good idea? Let me know with any hits or pointers. P.S. When it lost power it was very hot in Seattle area 92-95 and I believe it got vapor lock in the fuel system.

Thanks for the information of how-to..... I am planning on doing it tomorrow hopefully. The 1991 Lex LS400 has 174,800 mi. I already change the first fuel filter on the driver side on 6/28/06. I blow into the old fuel filter and black crud came out. Well, here is my problem: I was going home on 520 west and I was accelerating hard as the sweet Lex hums it's beautiful quiet engine to big rpms. All of a sudden around the last corner. It's a long "S" corner hitting the last part around 65m.p.h. coming out of 2nd gear into 3rd after hitting 6200rpm with ECT pwr mode on. All of a sudden it lost power as I hold the throttle to the floor. The temperature in WA is 92, As soon I gain control of throttle by releasing the pedal to close I immediately push down on the throttle and ease the girl at a cruising rpm of 2 grand at 60m.p.h. I add more throttle and it accelrate just fine to the point where it hit the 4000rpm - 6200rpm scale and the Lex suddenly "Lost Power" and it feels and hears like it hit the rev limiter if you were to do that. As soon as you hit 4grand it starts the "Lost of Power" 3500rpms drives normal. I lost power and speed quickly.I check the oil, tranny and it check o.k. Just for safety maintainence. Then my mechanic said, it wouldn't be a bad idea to check the fuel filter. Since it hadn't been change since I own the Lex. 3 1/2 yrs. At first I thought it was bad gas in the tank. I first put redline fuel system cleaner. Didn't seem to fix the problem but it may had help it. No, it's too late by then... So, after I change the first fuel filter I put the brand new Wix filter in the Lex. (reminder it's the driver side fuel filter) test the Lex. Same problem occur "Lost Power" same range 4k - 6200 rpm. One more thing I took the car to the local Chevron station to a tech. mechanic he said it was a unusual problem meaning more than just fuel filter problem? I said there's should be more testing. But I won't do it until after changing the 2nd fuel filter. I will let you all know how the process went of taking the 2nd fuel filter. That's my "Lost of Power" story problem....Any suggestions or ideas that would else cause the Lex to lost power in the power band range please add reply. Thanks Paul

I have a '91 LS400 Regarding where the fuel filter is exactly located inside the tank? When you pull the carpet cover away from tank there's a sensor gauge on the side as you looking right at it. And on top it looks like a breather for ventilation. Do you need to take the back seats out? I wish I had a manual at this time. Thanks Paul

One more thing before moving it over to the detail forum. Question #1. How many of you wash your car by hand? And second, how often do you wash it? Week, Month or Year. Try to the first two. Question #2 How many of you take your beatiful Lexus to the Car Wash "Brown Bear" or different name...but still it's done buy a commercial company. Question #3 How many of you vaccum your cars after or before washing the car? Thank you all for reading. From '91 LS400

Hi I have a '91 LS 400 One day I started from my house in Bellevue,WA with the orange light already on. From there, I travel to Tacoma,WA about roughly 31 miles and still going I had about 2-3 gallons left in the tank. If someone really want to find out go ahead and bring some fuel with you in the car and drive it until it exactly runs out but keep track of the miles when the light comes on. Sometimes the lights comes on and then goes away and finally then stays on firm. My tire pressure 32 psi. And everything is checks out fine. Paul

Thanks I got some good info. I'll try it. By the way, I was driving the Lex the trac OFF light and engine warning light automatically turn off for such strange reason everything works again. Now I don't kow if the Lex has a code. It won't to try it. I imagine something when bizarre in the brain of the ECU that day. And she"Lex" fix her self.

Hello It's me again, '91 LS 400 with 162k. A little background, I resolve the first problem...the alternator. When doing so... you must disconnect the battery. So I did. When it's time for reconnecting I forgot my code to unlock the SEC antitheft system for the radio. How brain dead or clueless of me to not write it down. I did feel pretty stupid of not doing it. I did learn a lesson and a nice price to get it fix. Lexus Dealer = $100.00 ouch! I need the radio back for nice pleasant rides. Well, anyway that was Aug. 4th 2005 when I took the Lex in for the service. Now today is 8/6/05 12:17a.m. Bellevue,WA time. Here's is the problem... I went to Safeway buy some goodies for tomorrow Seafair show of the Blue Angels. When I came back to the Lex start her up the Trac OFF indicator light came on and Engine system warning light came on both at the same time. I was thinking? Could it be that When the Lex was service 8/4/05. Couldn't it be that they may have mess with the trac button which is next to the radio. Trac button on '91 LS 400 is on the bottom left hand corner of the radio and its right above the ashtray, trac button. The Lexus ran beautiful like it always does. It did test out the trac system and no vibration came on as active or the trac light flash. I don't know what the engine system warning ligth means. It seems to me a broad problem without figuring out what symtoms to look at first. Let me know anyone if they had this kind of problem? And I probably going back to the Lexus dealer after some results from the lexus owners. I hope there's not a Part III to this story. Paul

Well everyone, The results came back and it needed a new alternator due to no voltage getting to it. And my caliper is fix too. Just keeping getting a defective one. And this time I've got a warranty on it for free. I appreciate your help.

Thank you for your response wwest... I appreciate it. By the way, I was wondering if all the LS 400's all come with a nice shiny shield for the alternators to keep heat away. My does and I know that not all alternators come with a heat shield. Right now, the car is relaxing and being charge with a battery charger to keep the battery fresh when it's time to put the new alternator in. It should all go well. It's a Denso brand alternator too. As I was working on the process today of taking the alternator out I had a left front side stuck piston caliper. I say it shouldn't be that hard to turn your wheel while the Lex is jack up. Right side caliper is fine. In fact, the left side caliper was replace 1 year ago with the same problem. It's an easy fix but I hope it last longer than a year?

I'm back with some results.... I went to my local auto parts store for a diagnosis of the charging system. The result came with the engine not running for the battery 12 amps. With the engine running (NO VOLTAGE GETTING TO BATTERY) 11.46 amps. A new cost $370 dealer, Lexus dealer. Next step I had in mind is to have it balance for checking to see if the alternator checks out around 14 amps. The Lex has 162k.

Oh! by the way I don't have a leaking power steering problem. I haven't check lately on the charging system. Meaning the battery? It has a new battery in it roughly 3 - 5 mths ago. I will check the alternator. Do you think it may be internal leak? I will check about for posting results.

Thanks I will try that and test it. I will let you know.

I try your advise for 5 min. worth. and it didn't seem to turn off the sensors. What's next in mind?

I have a "91 LS 400 Early this morning when the car was started some of the sensor lights stay on. brake, battery, engine coolant and engine oil sensor lights. Even when you pull the parking brake it stay on. I check the fluids levels and brakes and there were fine. I'm just wondering if there a computer module that controls all 4 sensors and they all went out all at once. Please let me know what it takes to get this fix. Paul

'91 LS 400 with Yokomama's AVS dB decibel S2 with 32's PSI running on 24k at this time. I really enjoy it.

Hi again, '91 LS400 The problem got resolved. First thing I tried was cleaning the sensor itself. There were green crud around the sensor and the needle was stick to the plate. So, no broken needle. Great advise and idea to check. That wasn't my problem. Just a little clean and there. The light hasn't come on since. Save me a run to the parts dept. It helps to read and prepare yourself before throwing parts at the problem.

Continued.... on ... Today, I did take a trip an round trip of 80 miles. It ran great. The light was on the whole time. It was warm weather here in the 60s in WA. Temp. gauge stay the same even when I was going at speeds around corners. I know that shouldn't effect the problem. I was just letting you guys know how I drive. I was carry a full load of passengers. Plus, an wheel chair for one of my passengers. It was great! Ran great. I new occurrance I had the cruise control on part of the way and I was accelerating with it because I had two other cars that were following behind. Not lexus but an BMW M-6 and just an Kia. I also use the deacclerating two. not to often. At one point of time the cruise control didn't like my commands with +/- with speeds of the cruise. It then, suddenly shut it self off and made the green highlighted cruise control to go away. I try to regain the cruise on my controls but no responding of any. And it didn't appear the green cruise on the instrument panel. I then, told myself that she playing with me. I then, ignore her and didn't mess with the cruise. When I arrive to my destination for lunch. I then, have my fun with my crew. After awhile, I when over to the Lex and started her up and the green light appear. Then, I shut her down. And finished enjoying my pre-Easter celebration. When it was time to go. I was curious of turning it back on. I did and it was back on normal it accelerate and deaccelarate like it should. I was then happy and feeling great about myself and the Lex again. It didn't occur any new problems down the road. THAT'S TWO PROBLEMS THAT SHE (LEX) PLAY AROUND WITH ME. I know it's long but it's good to share. Paul

Well for my Temp. gauge. It reads normal like it should in the middle. I check the car this morning and it was at the lower level. So I added some water so it would be between the two level markers. I then, started up the lex and suddenly in minutes the coolant light came back on. I then proceed to check the level and it was neutral. I then wanted to take out for an test drive up to Newcastle golf course. I got some good speed and warm the lex up thoroughly and then check it at the golf course. When hot, or normal temp. It was above the second level which is normal before the light ever came on. I then proceed on with my test drive. Afterwards, I still bug about the situations. I then, call the Lex dealer in bellevue. The guy said, that You might need to replace the sensor. Before he end the call with me he said try checking the cap on the sensor before replacing the sensor itself. Any good idea of checking the cap? Would that I have any cause or effect of this situation. He did remind me that the service center has lots of sensors. Paul

Hi "91 LS400 sweet & reliable 157,000 mi.

Hello I have "91 LS 400. Today when I was driving to go home. I went around a sharp upgrade hill incline about 25 m.p.h. into the corner. It's very sharp. Anyhow to this situation after climbing the hill with the Lex revving sweetly. I check my gauges and notice the engine coolant light was on. I was not far from home. So I drive home with TLC. I was being easy on it. When I pull into my driveway I check for any leaks and check to see if the level was low. It was not low but just over the top level mark. There's two level marks on the coolant box. I also turn off the Lex in the process. I cool the engine off with the hood up for awhile. To see if that would help any. And it didn't. It came back on with in minutes. I then talk to a friend who knows cars. He said from your situation that with the speed and g's force going around that sharp corner could offset an signal to activate the engine coolant light sensor to come on. True or false? Could it also be that the coolant sensor light be sticky?I believe it's not because when you turn the Lex on/off the light doesn't come on right away. When you turn it on to the Accessory position the coolant light works like it should. But that's not the problem. The problem is that it comes back on even for awhile of like 10 min. of waiting before starting again. Any solution to my problem? Do I need a new sensor or should I clean the sensor? Paul

Hello I have a ' 91 LS 400 It been doing the same vibration from the rear end of the car. like the others that I've read. When I drove it on any pave roads at any speed in high gear. Whenever I want to accelerate it seems that as it kicks down to the next gear it makes that vibration just for a momnent (1-3 seconds). In a day of lots of driving I get about at the most 5 respones for the backend. First thought came to mind was the driveshaft. It started to occur Dec. '03. If you agree or disagree that's fine. Just want to hear your response. Second thought, was the tranny. It seems fine and shifts great like it should. Next thought, check the records when the tranny fluid needs to be change. When I check it. It does need to be change. It shows a moderate color. Not to bad. Second owner of this LS. I wanted to convert tranny fluids over to synthetic oils. So instead of power flushing the system. I flush it by draining the pan. Which it hold 2qts. I use valvoline. This flushing method works well. I've been told that power flushing the system doesn't clear up the converter to make it fresh. It does clear up your coolant pretty good. I wait a week then drain the pan again. I did that for 8qts worth. 4 weeks total. I got one more week to finish the process. Once it done. I go ahead to convert over to synthetic. So far in about 3 weeks this LS has no problems with the vibration. I let you know if it does again. The longest time when it returns is a month an 1/2. Thanks for your time. Paul

I have a 1991 Lexus LS400 and it has a similar problem. I really don't know exactly where it is coming from. It has around 130k with a huge tune-up which includes new plug wires. The problem is: When you are driving around 45mph at light throttle it starts to glitch with a hesistation. It's not losing power,nor the fuel pump is low. It almost seems like the car is going out of o/d into 3rd and back into o/d but the tack (rpm) doesn't move at the hesistation. Going at full throttle and stomping on it works like a charm like it should. This problem only occurs at light throttle while cruising down the road. Could it be an O2 senser? or does the throttle body needs to be clean. I'm referring to curts message. Paul

Hello, I have a 1991 Lexus LS400. My problem is with the front console instrument panel where the radio/CD and climate controls are. I got many lights burnout when you turn it on at night time. Night time when it works best to see your problem and how many lights are burn out. My question is what is the best and efficient way to fix the lights. Yes, it has lightbulbs. Does any one know how to fix it and to post up a dialoque manual with picture steps to fix it. Thanks Paul.