I'm having an issue with my TPS. Sometimes my idle is too fast. When I look at the WhatsUp Display it shows my TPS sitting at 2 or 3% instead of 0. If I shut the car off, and restart, then the idle returns to normal and TPS correctly shows as 0%.
When I'm seeing this 2-3% reading, I checked the throttle body and cable to make sure that something wasn't binding and the blades are closed as they should be.

I haven't seen EBL throw any fault codes.

Do I have a bad TPS even without a code, or what else could cause this behavior?

Thanks

 

You probably have worn throttle shaft bushings and it's not always closing completely. The EBL uses the lowest seen TPS voltage as it's 0% and updates that accordingly every time it see's a new lowest value. This resets every time you cycle ECM power. So you are getting variations because the throttle is hanging up sometimes and completely closing other times due to shaft play. The hang-up is at a point where the EBL considers it to be slightly off idle and it's not actually entering idle mode. You may be able to adjust things so that even when it hangs up it's still in idling mode. My throttle body is worn such that I can't get the recommended 15-20 IAC steps. I can get 25, or if I get it to open a little further it snaps to a position where my IAC is around 6-8 steps. But it works ok at 25 so I have just left it there with the TPS set to 0.5v. As I'm upgrading to a FIRST intake here pretty soon I have elected to not mess with it. Seems fine at 25 steps.

GD

 

Thanks. Any suggestions on how I could check for that, and repair if necessary. That's not something I've ever messed with before. This Throttle body was purchased as 'Rebuilt' 2 years ago, so I'd be surprised if anything is worn on it already, unless it was never fixed during the rebuild process. r

 

Check for binding of the cable, and check for play in the shaft - hold the throttle blade open and try to wiggle the shaft side to side and up/down. If there is a lot of movement it's clapped. If there's not look for some other reason it's not fully closing at times.

GD