Perhaps the gas pedal. There are troubleshooting procedures available on the net.

 

donbrew - wasn't there someone here that had a similar issue with high idle speed that eventually returned to normal with several cycles of driving? but it took a week or so to resolve itself.

 

I remember that, the TB had to relearn parameters of it's limits program.

 

The relearn only takes 3 minutes of idling, or so my research says. Never had the problem myself, just reading.

As I remember, that other one never did post a resolution, Or it was something other.

 

I'm back again :)

Tested my car today for about one hour (out of the road of course)
In idle mode TB position - 25% according to OBD2
In idle mode accelerator pedal position ("D") - 19.2%
In idle mode accelerator pedal position ("E") - 9.4%

Acceleration sensor shows some random numbers between -0.1 and 0.9.

Now, how it works without all these numbers:

1. Turn on engine
2. About first 2 or 3 seconds RPMs are around 1k and TB is closed
3. TB is opened for about 50%, RPMs are around 3k (for 5 seconds or so)
4. TB is opened around 25%, RPMs are lowering till 800-900
5. Switching to "R" or "D" is not lowering RPMs
6. After touching accelerator pedal car starts moving (but it's not the same as "idle move on D while you just touch accelerator a bit"). It MOVES. RPMs around 1500, speed - 15-20 mph. And all this WITHOUT pressing accelerator pedal...


So it looks that smth wrong with accelerator. It's default values in idle mode not in normal state.

What should I replace in this case? Looks like accelerator pedal position sensor is not working properly...

 

It's not clear to me from your posts, but did you reset the ECU after the work mentioned in post #20? If not, that might be all you need. And, make sure you wait a while with the battery disconnected (at least 5 minutes). Otherwise, the ECU could still retain the info you trying to reset.

Whenever I have seen this kind of problem on a drive-by-wire engine, it's almost always been solved by cleaning the throttle body and resetting the ECU. I hope that's all it is, for your sake. If not, it's probably a sensor, but I don't know where to start with that.

 

I have 2006 chevy hhr replaced the throttle body and have a high idle ever since and I did all the things you all said drove it for a long way 150 miles or so still has a high idle. Can any one help or give clues? Does not seem to want to relearn at all no matter what I do. replaced throttle body because cleaned the old one and map sensor, tps sensor.

 

Read the whole thread , lots of suggestions, like disconnect the cable at the battery for 5 minutes at least.

 

Why did you replace the TB?
CheckEngineLight on?