Suneet

Hey guys,

So this happened about two months ago when I cleaned my throttle body, and after doing more research, I think its my TPS.

Basically what happens is when I'm driving on the freeway cruising at say 65, and I left off the throttle just slightly because I want to reduce my speed to 60, all of a sudden it feels like I feel the car shifts and it slows down a lot more than it would before. If i step on the throttle again, the car jerks forward as if its shifting again and there is more power.

You can see the RPM's jump suddenl from 2200 RPM to 1800 RPM and vice vers when I step on the throttle.

So here's the question: After cleaning the throttle body (which requires removing the TPS), do you need to adjust the TPS? The LexLS tutorial didn't say anything about adjusting the TPS when doing so, but it seems like it could need adjustment.

This was the tutorial I followed for cleaning the TB:
http://www.lexls.com/tutorials/EFI/throttlebody.html

I was just looking at his TPS adjustment thread:
http://www.lexls.com/tutorials/EFI/tps.html

Do I need to do this? Is this what is causing the "jumpy" highway performance?

Och

iTrader: (3)

Well, the TPS, whether it adjusted properly or not, should not cause any RPM jumps, as long as its working properly. I would check if its mounted back onto the TB properly, and I would also check for any vacuum leaks.

Suneet

I've got a vacuum leak.. the idle conrtrol valve hose that goes to the PS pump from the intake body. Could this be the culprit?

Jasbmo

Peter, listen, your problem is you need to put a cover sheet on the TPS report.

Suneet

Hahhahaha.. I love that movie. Especially the Indian guy.

NewLSlover

This has nothing to do with the throttle body, bro.

Mine does this too, mostly around 45-50..

I searched all over the net when I was more "in tune" with my car and found that all 1st gens are like this..it sucks.

GRAND_LS 4

iTrader: (2)

Sounds like your converter is locking up like it supposed too. Are you sure you didnt have this "issue" before?

Suneet

Yeah, I'm absolutely sure I didn't have this issue before. What convertor are you speaking of? THe TQ convertor? I noticed this huge change immediately after cleaning the TB.

So this is how its SUPPOSED to be? How annoying..

LexLS

Mine was jumpy at that speed range too after I replaced my TPS. With a little adjustment you should be able to get it smooth. If you removed the TPS when you cleaned the TB then I say your TPS definitely needs some adjustment.

...and no, it's not supposed to be like that! You'll get it .

Suneet

Thanks for the info man. You might want to update your TB cleaning tutorial at the end to say "you might need an adjustment", and link to your adjustment tutorial.

The thign is, my car is still idling at the correct idle.. just about 650.. so its gonna be tough to get this adjustment just right.

Suneet

I had the car serviced this week: did the full ignition system. Spark plugs, wires, caps, rotors, and ignition coils.

Magically, my jumpy highway performance dissapeared. Car rides buttery smooth. I need to drive it a bit more to be sure, but so far seems great!

GRAND_LS 4

iTrader: (2)

Maybe restting it, by disconnecting the battery did it?

Suneet

I spoke too soon! ITs back again! I think just like you said.. resetting the battery did it.. it has somethign to do with the way the transmission learns your driving patterns, I think. I'll be tryign to fix this, and when I do I'll post what I did.