I've got a 99 with 80K miles on it. It has always seemed to me that the throttle tip in response is abrupt, especially when you are in stop and go traffic and coasting slowly. In this situation, returning the car to speed seems to happen with a jolt, not a smooth acceleration. This is not like a sloppy driveline or anything like that, it's more that when you step on the gas, unless you are very sensitive with your foot pressure, there is not a smooth transition from coasting to speed. This also happens on occasion from a dead stop, you press the throttle down, down, down and then it jumps. This also doesn't feel like a transmission issue.

I'm sure that the throttle tip in response is probably electronially controlled. Have any of you experienced anything like this? If so, what were the solutions?

This is not a horrible problem, but a car of this refinement should transition to acceleration with more finesse.

Thanks,

 

Have you tried to reset the ECU? Sometimes driving habits change over time. Resetting it and letting the ECU relearn is a good free/easy fix. Do a search and you'll get info on other feedback. Some even reset the ECU regularly on a schedule.

As to how, you can pull a fuse (can't remember which right now) or disconnect the battery ground for a minute or so. You'll lose some settings (which depends on which reset method used) but the throttle response may get better. Again, a search will give you a bunch of info.

Anyway, you have nothing to lose except for some settings.

Good luck.

 

Sounds to me like your throttle body needs to be cleaned, because of the sticking throttle plate/butterfly.

 

I thought of this possibility too. It is just a little more involved (DIY-wise). If the reset does not help. then I second this as a possibility, especially given the age of the car.

 

I don't mind tackling a fairly complex DIY task. I've also got a '90 944 S2, '91 4runner 4x4, plus a couple of commuter cars all of which I maintain and have done all the standard stuff (alternators, fuel pumps, starters, struts, timing and balance belts, etc.) The GS is my wife's car and I don't know that much about them. They seem pretty straight forward. Would you guys recommend the Lexus shop manual, or one of the others like Haynes?

Thanks,

 

The Lexus shop manuals are useful but are expensive (a few hundred last I remember). If you plan on tinkering with the GS, then it is nice to have them. Here is also a link to Dex's page on cleaning the throttle body to get you started:

http://www.digitalsimple.com/The%20G...rottleBody.htm

Good luck.

 

I'll reset the ECM and clean the TB. Thanks very much!

 

Hey any luck with cleaning the throttle body and resetting the ECU by the battery terminal?

 

Maybe I can help. I had the same issue and noticed that the throttle cable had some slack in it when I changed my valve cover gaskets. Before I had to push the throttle in a bit before the engine would respond and then it would jerk forward. I adjusted all of the slack out of the cable and now its nice and smooth from a stop and even the smallest bit of throttle changes the engine RPM and no more jerk from a stop.