Help! Guytelefunken, Dcfish, And Others In The Know...

topichka · September 18, 2006

Hello All,

First off, thanks to the above mentioned for your knowledge and your willingness to share with others on this forum--you've saved many a dollar! I have an 01 GS430. The car drives perfect EXCEPT for one issue. Often times, the car feels like it's cutting out on me while driving--like it looses power for a few seconds. To be more precise, it's as if I take my foot off the accelerator and downshift but I do neither. My foot remains firmly planted in the same position but the car definately loses power. I compensate for this by stepping harder on the accelerator and the car springs back to life but it seems like I have to press down an extra 1/2 to get the same acceleration as before. I definately have to apply more pressure. I've looked around and have heard people mention similar issues. People suggest replacing the TPS, MAF, cleaning the MAF, cleaning the throttle body (I've cleaned both and neither were very dirty). I've heard of a few people who've replaced their "accelerator pedal assembly", APP part #78010-30030 and this seemed to remedy their problem. So, based on this knowledge, I called the dealer and ran all this by the service guy. He said there isn't any sensor related to the accelerator and he even went as far as to fax me the parts diagram, I couldn't find a sensor either. I asked another local shop that works on Lexus and he told me that he's never heard of anything like this before. He too, mentioned that there wasn't a sensor in the pedal assembly. I'm not made of money and would like to spend my $$ wisely. I'm tempted to order this part anyway and have them install it but thought I'd check with those of you that seem to know a great deal about these fine cars. Also, this issue appears to happen much more frequently when the weather is hot. It doesn't appear to do it when the car is on cruise control, and lastly, it might not happen for weeks at a time, and then one day, happen 5-7 times in one day. THANKS IN ADVANCE EVERYONE FOR YOUR HELP!

dcfish · September 18, 2006

Hello All,

First off, thanks to the above mentioned for your knowledge and your willingness to share with others on this forum--you've saved many a dollar! I have an 01 GS430. The car drives perfect EXCEPT for one issue. Often times, the car feels like it's cutting out on me while driving--like it looses power for a few seconds. To be more precise, it's as if I take my foot off the accelerator and downshift but I do neither. My foot remains firmly planted in the same position but the car definately loses power. I compensate for this by stepping harder on the accelerator and the car springs back to life but it seems like I have to press down an extra 1/2 to get the same acceleration as before. I definately have to apply more pressure. I've looked around and have heard people mention similar issues. People suggest replacing the TPS, MAF, cleaning the MAF, cleaning the throttle body (I've cleaned both and neither were very dirty). I've heard of a few people who've replaced their "accelerator pedal assembly", APP part #78010-30030 and this seemed to remedy their problem. So, based on this knowledge, I called the dealer and ran all this by the service guy. He said there isn't any sensor related to the accelerator and he even went as far as to fax me the parts diagram, I couldn't find a sensor either. I asked another local shop that works on Lexus and he told me that he's never heard of anything like this before. He too, mentioned that there wasn't a sensor in the pedal assembly. I'm not made of money and would like to spend my $$ wisely. I'm tempted to order this part anyway and have them install it but thought I'd check with those of you that seem to know a great deal about these fine cars. Also, this issue appears to happen much more frequently when the weather is hot. It doesn't appear to do it when the car is on cruise control, and lastly, it might not happen for weeks at a time, and then one day, happen 5-7 times in one day. THANKS IN ADVANCE EVERYONE FOR YOUR HELP!

topichka, Welcome to the forums :cheers: How many miles on the car ? Does it occur at a certain RPM ? Has any service/maintenance been performed recently ? :unsure:

I found this: Hope it helps. ;)

throttle_position_sensor_GS.pdf

nester · September 18, 2006

..

Also, this issue appears to happen much more frequently when the weather is hot. It doesn't appear to do it when the car is on cruise control, and lastly, it might not happen for weeks at a time, and then one day, happen 5-7 times in one day. THANKS IN ADVANCE EVERYONE FOR YOUR HELP!

Hi, I have absolutely the same on my 01 GS430.

Throttle body cleaning - doesn't help. ECU resetting - (apparently) doesn't help.

Also what we noticed here - this issue connected to driving style - e.g. it significantly more often when my wife is driving (more gently) then me (more aggressive). So start "pushing the pedal" - might become better ;)

Also it's noticed to be more often in such situations - when you slightly deaccelerate (release pedal 2 mm) for a few seconds and then accelerate again (press for 2-4 mm) - it happens.

Also car seems "stuck" on the gear - you can floor the pedal - it will stay the same 5th. (Release and press again - it will "catch up").

OK, what helped me a lot - cleaning battery terminals. Went to dealer, paid $120CAD and they have it done. :rolleyes:

OK, they made everything what they could test - no codes, no history codes, testdrive was OK (yeah, sometimes it runs for a week without problem), inspected everything under the hood, and at the end found dirty terminals and cleaned them.

So right now problem is solved 95% - sometimes car loses power, but to quite small degree and not very annoying.

(Might need to replace battery? Battery is tested to be OK, but it's 5 year old..)

Anyway if you find the _real_ solution - please keep me posted. (BTW, do you speak Russian? ;) )

I'd like to have it fixed 100% - "anything beyond perfect is not acceptable" ;))

Dcfish - thanks, will have my mechanic to test TPS as you've attached.

topichka · September 18, 2006

..

Also, this issue appears to happen much more frequently when the weather is hot. It doesn't appear to do it when the car is on cruise control, and lastly, it might not happen for weeks at a time, and then one day, happen 5-7 times in one day. THANKS IN ADVANCE EVERYONE FOR YOUR HELP!

Hi, I have absolutely the same on my 01 GS430.

Throttle body cleaning - doesn't help. ECU resetting - (apparently) doesn't help.

Also what we noticed here - this issue connected to driving style - e.g. it significantly more often when my wife is driving (more gently) then me (more aggressive). So start "pushing the pedal" - might become better ;)

Also it's noticed to be more often in such situations - when you slightly deaccelerate (release pedal 2 mm) for a few seconds and then accelerate again (press for 2-4 mm) - it happens.

Also car seems "stuck" on the gear - you can floor the pedal - it will stay the same 5th. (Release and press again - it will "catch up").

OK, what helped me a lot - cleaning battery terminals. Went to dealer, paid $120CAD and they have it done.

OK, they made everything what they could test - no codes, no history codes, testdrive was OK (yeah, sometimes it runs for a week without problem), inspected everything under the hood, and at the end found dirty terminals and cleaned them.

So right now problem is solved 95% - sometimes car loses power, but to quite small degree and not very annoying.

(Might need to replace battery? Battery is tested to be OK, but it's 5 year old..)

Anyway if you find the _real_ solution - please keep me posted. (BTW, do you speak Russian? ;) )

I'd like to have it fixed 100% - "anything beyond perfect is not acceptable" ;))

Dcfish - thanks, will have my mechanic to test TPS as you've attached.

Hello dcfish and Nester--thanks for the help. To answer your questions dcfish--I have 122K on the car, it doesn't appear to happen at any certain RPM, although it's never happened when I'm really on the gas(something Nester mentioned) and I've not had any recent service that might have triggered this. Also, thanks for that attachment but I'm pretty clueless when it comes to that stuff. Nester, it sounds like we're on the same page with the car--you've described my situation exactly. My battery is good--nice and clean so that's not an issue on my end. I'm going to attach a link to another forum (I don't know if this is considered improper but I figure it's all about sharing info for a better experience). There are a couple of people who've seemed to experience the same issues...Thanks again!

http://www.clublexus.com/forums/showthread...position+sensor