knowtoe04

Hi,
I have an '01 GS430 with about 64k on it. Lately it's been "cutting out" on me meaning that when I am driving, cruising mainly, down the road it is like I took my foot off the pedal which I have not. After that happens it's almost like the pedal is "mushy" and I can't get the car to respond unless I really press on the gas. I had a voltage problem a while back but a new battery fixed that.

It seems to happen mostly between 30-60 mph and mainly when I am in town. If I drop the car down a gear and get the RPM's back up it seems to respond and come back to life. If I really punch when I am getting on the freeway it does great. Most of my driving is in town and I always have the ECT/PWR turned on.

Any thoughts or comments is greatly apprectiated. Thanks.

Patrick

TLW

ever get a CEL(check engine light )

do you have any mods done to the car

knowtoe04

Nope, no CEL and no mods to the car.

sputniknyc

iTrader: (2)

fuel injectors ok? check spark plugs?
sounds like fuel related to me

Billh2

First step would be to have the codes read. I have been told that AutoZone will do this at no charge.

JellyBean

I have the same problem and several others have posted similar complaints. Search for "laggy" performance and "hesitation". This is, I believe, the GS430's only major drivability issue. And I call it "major" because it's very irksome in an otherwise flawless car.

Anyway, as you search and read you'll run into the homebrew remedy of disconnecting your battery or removing a fuse to reset the ECU. I tried that and it didn't work. What DID work, at least temporarily, was for the dealer to reset something somehow somewhere. The dealer's lame explanation (and one that you'll see posted too) is that the hesitation is a sign that the car is "learning" your driving habits, and that once it learns, it'll function correctly.

If that's the case, then my GS430 is dumb as sh@t. The dealer's reset (last October or November) lasted for exactly 3 weeks, before the car started acting up again. It drove like crap for a few more weeks, and it then drove flawlessly all through the winter. Unfortunately, about a month ago, it started acting up again. I'm now hoping that the issue disappears as suddenly as it returned.

I don't buy the "learning" stuff. I believe that there's either a software or hardware design flaw somewhere along the system. Notice that it doens't act up when accelerating or decelerating under cruise control. Also, any "learning" features would've been pounced upon and fluffed up by the marketing department. Nowhere in all the literature that I've read does Lexus mention a "learning" throtle. That's enough ranting for the day. Good luck.

JB

EDIT: Hey, I just saw that you posted about a similar issue back in August about a mushy pedal, and I posted a similar reply (at least I'm consistent ). Are these the same issues?

TLW

they do when you have a CEL

im prettty sure i just saw that they also check your starting system

knowtoe04

JellyBean,
Ya, I posted the "mushy pedal" thread and that turned out to be a voltage problem which a new battery promptly fixed. This feels a little different and really does feel like some turns off the car. It happens mostly in the morning (cold) and at between 30-40 mph. Happens in town 95% of the time. Could it be the tranny?

It's at the dealership right now and of course the first day "it didn't do it for them". With all of that computer gear in it it's got to be telling them someting if they would just read the codes. If the service rep says they can't find it and tries to charge me $200 for a drive I will be really upset. I think I am going to try to talk to the tech.

It has good days and bad and at this point I am ready to sell it if they can't fix it. Thanks.

Fisher503

I had something very similar. Almost made me sell the car and get an S4. Do you have an k+n filter or other type ever on the car? The Mass air sensor can make your car do exactlly what you described and never cause a CEL to come up! By the way I have a 2001 GS430. Carson wants 160 for the part I got the dealer to cover it and right back to the way I remember the car. The dealler kept telling me there was nothing wrong the the tech changed the Mass air an he called me right away and said "Holy ***** there was something wrong I'm giving it gas and lighting the tires up all over the dealership."

knowtoe04

Fisher,
The car is pretty much stock all the way around. When you say K&N filter I am assuming you mean an air filter. So you are saying that a new mass air sensor fixed your problems...which sounds like mine? How did you convince the tech and the dealership that the air sensor was the problem?

Again, I hope this kind of stuff shows up in the codes. Thanks for the tip.

Patrick

Fisher503

I told him order the part lets try it and if it doesn't work swithch it back . Tell him that there is 3 things it could be :
TPS
Throttle Body
Mass Air
The mass air is 95% the cause, it could also be the others. So tip him well and he will change all three for you. Any other questions let me know.

knowtoe04

Great...thanks!

What is the TPS?

chuckb

my 430 never had a miss, but the low idle with the air off prob became a little worse. I took it to the dealer and they replaced MAF(car had 26k miles) and now it's fine.

Fisher503

TPS= Throttle Position Sensor.
That part is like $63 at Carson.

JellyBean

Knowtoe4
Thanks for the feedback. I'm printing this thread to bring it to the dealer when I take the car in for the 60K service next month.

Anyway, I don't think it's the tranny. The best that I can describe the symptoms is that while I'm trying to hold a steady throtle--either around town or in the highway, with the car fully warm and randomly--it *feels* as if the GS suddenly turns off a bank of cylinders, losing power and becoming sluggish. There are no noises, vibrations, or visual cues. I treat the symptom by immediately releasing the gas pedal completely. Even my passengers comment on *my* jerky driving.