Hesitation

[telephoneman]

I've had my 2001 ls430 for about 5 years and it's always had an intermittant problem with hesitation (it kind of stutters then goes back to normal). Lately there is another symptom - you are driving along at a steady speed and it starts to slow a little and you have to press the accelerator down to get it back up to speed.

I suspect the accelerator position sensor. I've bought a secondhand one to test it out but I was wondering if it's just a matter of disconnecting the Battery, changing the sensor and reconnecting the Battery or will it have to be matched to the electronics under the hood.

Any ideas?

tia

Liam

[steve2006]

According to the service manual it's "plug and play"

[ColinBarber]

Are we talking about the throttle position sensor (TPS) mounted on the throttle body or the pedal position sensor? Not sure if the LS has the later but the GS430 does.

The TPS requires set up - it has slots where the mounting bolts go through allowing it to be rotated which allows the correct throttle angle to be read.

[telephoneman]

I'm referring to the Pedal position sensor. I was wondering if it had to be "paired up" in any way with the TPS.

[steve2006]

I have the later LS400 factory manual which explains the proceedure for removal and refitting ( basically the same as the LS430).

If you would like the relevent section feel free to PM your email address and I'll send it to you, this would also show you have to do the various tests on the throttle body motor and TPS which may help your diagnosis.

[ColinBarber]

I'm referring to the Pedal position sensor. I was wondering if it had to be "paired up" in any way with the TPS.

No the pedal position sensor has no adjustment. It is much more critical on the TPS because you cannot have any dead zone at the fully closed position otherwise the butterfly wouldn't open correctly at idle.

If changing the sensor doesn't fix the issue then I would look to clean the throttle body and check the TPS adjustment.

[deelcee]

my 2001 ls430 has developed exactly the same problem over the past few weeks!

be very interested to hear how you got on Liam.

[n4chv]

Maybe a garage (not necessarily a Lexus one) can diagnose the problem for you.

Could be either a throttle sensor or an issue with the Air-Flow mass meter. I've not heard of this issue before on the LS400 or LS430

[royoftherovers]

Has anyone asked the question of "Honestjohn?"

Go to honestjohn.co.uk

Good luck.

Regards

John

[telephoneman]

I haven't had a chance to change the pedal sensor yet but I'll update the tread when I do. I've previously cleaned the Mass Air Flow meter and it didn't change anything.

[Malc]

did you ever check the ordinary air filter ??

Malc

[telephoneman]

The fault has been around for several years and the air filter has been changed several times. If I go on a 200 mile trip it might occur once or twice. Needless to say, never when a mechanic is in the car. It also doesn't bring up any fault codes.