Throttle Problem With 98 - 99 Gs Series

[trand4]

Hi all,

I am glad to be here, with some of the experts.

I've been looking into buying a 98-00 GS300. After a brief research,

I found out Lexus issued a recall on the 98-99 GS models.

According to one of the comments I have read, the "throttle sensor" malfunction

caused the car to race at full speed for a number of seconds without the driver's direct control.

Is this true?

I really appreciate if some of you can shed light on this.

Best regards,

dt

[arsmtts]

I don't know if that's true, but I did have a problem with throttle sensor that caused my gs400 to stall as if the transmission was shot. I had to have it replaced (warranty of course).

[Ralow]

Yeah, I have a similar problem with my 1999 GS3. It seems that my transmission is "slipping" when I slow down to almost stop then accelerate again. Its like it hesitates before it takes off again instead of a smooth acceleration. I talked to the dealer and they told me it was the computer getting used to my driving habits. What? Anyway, it seems like they have no idea what it is and no one else seems to know either that's why I'm trying to get into a GS4 but I don't know now if it has the same/similar problem. Sometime it goes away if I use the "power mode" button but I don't wanna drive around with that on all the time.

[Rodders]

Yeah, I have a similar problem with my 1999 GS3. It seems that my transmission is "slipping" when I slow down to almost stop then accelerate again. Its like it hesitates before it takes off again instead of a smooth acceleration. I talked to the dealer and they told me it was the computer getting used to my driving habits. What? Anyway, it seems like they have no idea what it is and no one else seems to know either that's why I'm trying to get into a GS4 but I don't know now if it has the same/similar problem. Sometime it goes away if I use the "power mode" button but I don't wanna drive around with that on all the time.

You can temporarily solve this by resetting your ECU.

It's not the problem that Trand4 was asking about though. I have a 98GS300 and have not had this problem.

[Ralow]

You can temporarily solve this by resetting your ECU.

It's not the problem that Trand4 was asking about though. I have a 98GS300 and have not had this problem.

How do I do that? Cuz I'm trying to sell my car because of this problem.

[Rodders]

Easiest way is to disconnect the battery for 10 minutes or so. Make sure that you know your radio code (if you have one) though.

[JPI]

The TPS on GS's go bad all the time. Other than that GS are really good cars.

[kandygs400]

hahaha...u know what...i just found out today my throttle sensor was bad...i was having problems my check engine light came on and when i would try to go i had to but the pedal all he way to the floor for it to even get gas...only problem ive ever had with this car...but its gonna be fixed

[99blkgs]

did any of your guys cars have this symptom. the car idles at like 1600 rpm when starting it when the motor is cold and this lasts for a few minutes, thanx in advance

[GSKeef]

I dont know about your throttle prolem but many cars idle high when its cold to warm up the engine this is very common

[elementalbeats]

I have had several problems over the last month with my 99 GS300. Thought my tranny was sticking- flushed refilled and filtered it. Did not stop the extremely rough shifting. Gradually got worse to the point that it jumped from idle- just recently decided i was going to slow and accelerated to redline while driving down the freeway- lost all speed control other that braking. needless to say by the time i got to stop my brakes were cashed. now it either redlines upon startup or gas pedal doesnt provide anything. dealer told me he hadnt heard of any problem with gs300's and throttle control- told me i was crazy and there was no way the car accelerated w/o pushing the pedal- tried to tell me i was pushing both pedals????? after 10 mins of fighting to not get killed on the freeway and safely get off of it- i think i may have been sure i wasn't hitting the gas pedal. newayz - need to know how to remedy this problem. pedal position sensor error, and throttle plate open/closed. have thorouly cleaned the entire t.b. and am dumbfounded what else to do....please help

[mikejsam]

did any of your guys cars have this symptom. the car idles at like 1600 rpm when starting it when the motor is cold and this lasts for a few minutes, thanx in advance

yeah, i have a 98 GS 300 and when it hasn't been started for a few days (or just overnight) and the temperatures have been around freezing, the RPM's idle around 1200-1400. It doesn't seem to cause any issues. I tested it once and noticed that after the engine gets to its normal heat range operating temperature, the RPM's drop back down to a normal 400-800 RPM idle.

hope this helped!

[GS3HUNDRED]

I've got a 98 GS300 recently i've had to deal with the check engine light and both VSC lights all coming on while losing all acceleration ability unless i completely floor the gas pedal.

The acceleration comes back to normal if i shut the car off then back on but the warning lights will all stay illuminated.

After getting a diagnostic check the codes read the Throttle Position Sensor has failure.

So a few hours ago i disassembled the Throttle Position Sensor which sits right on top of the engine, i cleaned it but theres no way to tell that its bad by looking at it.

I need to replace it with another TPS. too expensive from the dealer though.

any ideas where to get this part cheap?

[scottelble]

I dont know about your throttle prolem but many cars idle high when its cold to warm up the engine this is very common

I thought i read some where that they idle high starting off to warm the engine quicker? I'm not a mechanic but it kinda makes sense.

[Hawkfe]

I've got a 98 GS300 recently i've had to deal with the check engine light and both VSC lights all coming on while losing all acceleration ability unless i completely floor the gas pedal.

The acceleration comes back to normal if i shut the car off then back on but the warning lights will all stay illuminated.

After getting a diagnostic check the codes read the Throttle Position Sensor has failure.

So a few hours ago i disassembled the Throttle Position Sensor which sits right on top of the engine, i cleaned it but theres no way to tell that its bad by looking at it.

I need to replace it with another TPS. too expensive from the dealer though.

any ideas where to get this part cheap?

I'm sure you already know Lexus parts aren't cheap. Search the forum, there's a member from Wisconsin that works at a Lexus dealership that will get you a discount. I just ordered my fron door lock actuators and he saved me about $54 per side.

[sakataj]

really.........thats good to know BUT why dont u post something up here letting us know his name or what not to make it easier to contact him! did you put your own door actuator in? im fixing to have to do mine and wanna know how much of a pain it is!

[GS3HUNDRED]

I ENDED UP CHANGING THE THROTTLE BODY ON MY GS300 TO FIX THE PROBLEM. JUST CHANGING THE TPS SENSOR

DID NOT SOLVE ANYTHING. NOW THE (VSC, VSC OFF) LIGHTS ARE GONE AND THE CAR RUNS SOLID.

[sakataj]

um u shouldnt have had to change your throttle body though! makes no sense.......especially if its just the sensor!

"i will welcome myself back to the forum as im,woo hooooooooo, finally unsuspended! hahaha!"

brian

[LexDiamondLS400]

Yeah, I have a similar problem with my 1999 GS3. It seems that my transmission is "slipping" when I slow down to almost stop then accelerate again. Its like it hesitates before it takes off again instead of a smooth acceleration. I talked to the dealer and they told me it was the computer getting used to my driving habits. What? Anyway, it seems like they have no idea what it is and no one else seems to know either that's why I'm trying to get into a GS4 but I don't know now if it has the same/similar problem. Sometime it goes away if I use the "power mode" button but I don't wanna drive around with that on all the time.

I had a similar problem when I purchased my GS. I had probs with hesitation when accelerating from 1st to 2nd gear as if the transmission was slipping, I reset the ecu and it temporalilly fixed it. Then one day the vsc and traction control lights both came on and I lost all power when pressing the gas pedal competely to floor. Took it the dealer the next day had them check the car out and run a diagnostics. They said the tps was fine and went ahead and flushed the throttle, they aslo cleaned the air mass flow thingy out LOL. Final thought I took the car home reset the ecu one last time drove the !Removed! out the car to let it adjust to my driving patterns, I put about 20 straight miles on the car after he reset, end result no probs for the last 4 months car drives like a dream and accelerates like new. I've had no probs with vsc/traction lights coming on nor probs with lack of power or acceleration.

I hope this information is helpful and useful, cuz I was pretty annoyed by those problems abd alittle upset lexus had no idea what was wrong. There was a post here a while back referring to this topic which is where I got the idea about cleaning the mass air flow and flushing the throttle. I actually recommended that to lexus and they agreeed since my car was still under warranty. So thankx Lexus Forums. The search button does wonders!!!

[Golden child]

Hi guys! I have had the problem of the hesitation, and wanted to sell the car, but I got a check engine light reading that said knock sensors bank 1&2, changed those, and the results were amazing, no more of that, but now I have the after sitting for a while, start, put in gear, and have to stomp pedal to the floor or pump the pedal a few times before car gets going, but once it gets going, it’s great from there, just only after sitting for a while, could this be the TPS? 

[Mega]

I have a 99 GS300 also and my car did the same. It accelerated on the highway without me pressing the gas. I had to get my back brakes and rotors and calipers fixed. A week later my car wouldn’t accelerate at all and all the lights came on. My mechanic replaces the throttlebody but it did the same thing. What else can it be??

[Cory549]

On 10/5/2007 at 2:59 PM, 99blkgs said:

did any of your guys cars have this symptom. the car idles at like 1600 rpm when starting it when the motor is cold and this lasts for a few minutes, thanx in advance

Lexus is known for high idle when a cold start. Suppose to help with emissions. I hate it. Mine does that.