I have a 2001 GS430 and it has an acceleration hesitation problem. The car is stock. There are no check engine lights or warning lights on. It's not just a slight hesitation. It's is very big difference in power loss and response. If I accelerate progressively it is fine. But if I floor it(full throttle), there is no response or power. The car doesn't seem to want to down shift but when it does, it sputters. This only happens when you floor it otherwise it drives normal with no problems. I tried cleaning the MAF, throttle body, air filter, etc. I'm thinking it has to be a sensor or something. Maybe a sensor for the accelerator??? I searched a little but no solid answer or solution. I was wondering if anyone else has had this problem? Any input?? Any help would be appreciated. Thanks!

 

You dont have any CEL?

 

Yep, no check engine lights. That's why it's so strange to me. The car drives fine with normal driving. But at wide open throttle it lags big time, it bogs down and doesn't want to go.

 

unplug the battery and let it sit. reconnect and see if the issue is still there. i had this happen a while back. turned out to be a bad MAF sensor. i cleaned it too but that didn't help. had to go grab a new one at the dealership

 

Wow! Same year, exactly same problem. I have 2001 gs430 with 92,000 miles on it, and I've had it since new. I have gone through an Injen air intake and now a K&N in the stock box, so there may be some years of goop on the MAF that the solvents and cleaners just can't defeat.

I tried cleaning MAF, resetting ECU (disconnecting battery) with little effect. Flooring the pedal makes for the worst feeling (hesitation, hopping, etc.)

Since it is easy to do, and hovering around $100, I'm going to try replacing the MAF.

 

I had this same problem. If I slowly accelerated, my car drove fine. If I pressed on the pedal more than 1/4 of the way, my car wouldn't accelerate and the car would just kind of rumble. Turned out my 3rd cylinder was misfiring. Hope this helps a little

 

What do y'all use to clean the MAF?

 

My 01 GS430 has 110K on the clock and this problem is happening more and more ..... my hesitation occurs of you push the pedal down about halfway quickly. Moderate pressing of the gas is just fine but it is too the point that I wait for LOOOOONG gaps in traffic before turning in now.

CRC Mass Air Flow Cleaner is available at Auotzone, Advance Auto parts and Pep Boys.
I used this stuff (along with the Throttle body cleaner on the TB butterfly) once and it seemed to alleviate the problem for a few weeks but it is doing the same thing again.

Is Sewell or Carson the best place to get an OEM Lexus Mass Airflow sensor ?

DaveC

 

RocketSlug and BossGS4: It sounds like we are having simliar problems. I used the CRC cleaner also but no help. Also tried resetting ECU. Still has the problem.

Lamchop21: what did you do to fix the misfiring problem? Did you replace sparkplugs? coilpack?

Anyone else have suggestions or solutions? Thanks!

 

I was having same problem and a trans fluid flush fixed it. Lexus only did changes on my car and never a full flush. 2001 110k. Trans flush helped me.

 

Try creating the problem several times in a row to see if it will throw a CEL. Did you hook up a ODB II reader to see if anything was stored? There might be something there without a CEL.

 

The gs400 has the issue with the throttle cable ... thought I read the 430 had that issue fixed? If there was slack wouldn't that cause the delay? Not to mention tranny flush like dwoods said. Could be more that one issue...

 

No, we don't have a cable like the 400. We fly by wire. We have a throttle position sensor. There is some delay when you floor it. This could be your problem.

 

I have a 98 GS400 and 01 GS430. I know that the 430 has drive by wire and the 400 has cable. I do realize that the drive by wire does have a slight delay. But that is not the problem. The car sputters and very hesitant when floored. It seems like when at 50% throttle the car pulls very good and hard all the way, with no problems, But when you floor it...it just bogs down and sputters. Then sometimes a surge of power will come back.

I did hook up my OBDII scanner but no codes were found and no CEL. This is why it's so frustrating. I might just end up taking to dealership to see what they can find but I just been too busy. Thanks again!

 

Ok, team. Took the plunge, replaced the MAF sensor. Night and day difference! I didn't remember this car could be so fun. When the brain is in trouble the whole body suffers, and this was the case.

Here is the rundown: Disconnected battery, unhooked stock intake cover (as if i was changing air filter,) rotated it, took connector off MAF, unscrewed the screws (these are small, tight thread, and a pain, so don't lose them) put new MAF in, and the connected the battery right up. Started right up (unlike post MAF cleaner days) and was suddenly quieter, with a more stable idle.

So, that was cool, but how did it perform? Every inch of pedal travel now has a response. I went from what felt like three foot positions (easy, medium, and after a delay, max) to what now feels like 0 - 100% based on foot position I put it in sport mode and the car was an animal I hadn't seen in YEARS!

Mileage went up 10%! No kidding. The computer was getting bad info from the MAF (which was almost 8 years and 100k old) and making everything wacky.

I blamed the transmission. I blamed the throttle position sensor. I never looked at the fact that the computer may be acting on BAD intel. WOW WOW WOW.

How much gas/transmission fluid/synthetic oil did I waste by changing it often hoping I was getting rid of the demons? A $100 sensor changed this car's life.



P.S.: JLAM: I had a 98 before my current 01.. .thought I'd never meet someone else. 98 GS4 was faster in every way, and I MISS the shift buttons, the spreadsheets of mileages/distances, etc and the overall clean button layout for the GPS.