XYZLexus1

I drove a 2001 GS 430 today with 59K miles. It had a serious flaw. Everytime I gave it gas it had a HUGE flat spot, at one time I could push the accelerator 1/4 way down and the car would not go any faster. Is this normal? My GS300 does not do this. The power was better than the gs300 but no where close to the LS430 I test drove. It had navigation, Mark levison and they were asking $26900 at a Toyato dealer. It had all the snap crackle pops mine used to have and the center console rattle mine still has. Exterior was excellent shape, interior was good shape. My big question is if the "flat" spot is normal?

JellyBean

I don't know if that's normal, but mine has the same problems at low throttle openings. When driving the car gently, that flat spot is very noticeable and disconcerting. When driven like a bank robbery getaway car, acceleration is instant and overwhelming. I'll be taking mine to the dealer next week or so and have them look at it. The posts around here indicate that this is a common issue caused by the ECU adapting to your driving style, and that a possible fix is to reset the ECU by disconnecting the battery for 1/2 hour. I haven't tried that fix so I won't comment on it. I hate to think, however, that such a high quality car would have such a common and noticeable problem.

GSpeed

I have the 400 and have the same problem. Tried the resetting the ECU thing and I could not tell any difference. The flat part is very annoying. Can't seem to get the proper throttle response when I need. Like JellyBean said, when you floor it... ITS ON! But there is such a large part of the powerband that feels delayed or not as responsive as it should be.

I've seen posts that tightening the throttle cable is another likely solution. I got mine tightened and throttle response inproved very marginally, but the probelem is still there. Maybe it needs to be tightened some more. Some folks have reported that tightening did the trick. For me, the jury is still out. One thing is for sure, it seems to be a common issue in the GS4, but does not effect everyone.

JacobT

This hesitation sympton has been discussed here extensively. Basically it;'s due to drive-by-wire and Toyota software issue. Lexus denied the design flaw so the only thing we can do to fix it ourselves is to install the after market high stall TC to get around this problem.

Check the other post about the TC install, it pretty much gets rid of the hesitation problem at take off.

JellyBean

Roger on the TC, JacobT. No TC for me, however. My car's a daily driver that'll remain stock for the foreseable future (except for L-tuned shocks next month). But I wonder if everyone is referring to the same hesitation. You correctly point out that the GS430 has the electronic "drive-by-wire" throtle control. But other people are complaining of a similar hesitation in pre-2001 cars that have the mechanical cable-controlled throtle. That's why I was trying to get smart on this problem before I take it to the dealer next week. I'll post results.

JacobT

The pre-01 2nd gen GS are also drive-by-wire. They have the cable as the back up in case the throttle motor failed. That's why all 2nd gen GS (98-04) have the same hesitation issue. I really wish someday, Lexus will issue a TSB for this problem

RRocket

Jelly,

Why not get the TC? Is as transparent as your L-tuned shocks when using it just for driving, and presents no driveability or reliability issues. I've driven cars with aftermarket TC for 10's of thousands of miles with no issues. All on my daily drivers....

JellyBean

JacobT: Didn't know that all second generation GS's had electronic throtles. Guess I'll try disconnecting the battery if the problem persists. Thanks.

RR: Hah! Are you spreading the mod virus? Really, I've been away from performance mods for nearly two decades and my knowledge of TCs may be outdated. I equate TCs with harsh shifting and recalibrated shift points. Maybe its time to read up on modern TCs. Still though, I must resist , I must resist...