skyline26

stale thread but I have the same issue
cleaned my TB last night. Took off the air hose, left the maf sensor inside the intake tube (put it aside so i didnt get it sprayed with the TB cleaner) , unplugged TB, and removed it. Sprayed it with cleaner and wiped it clean while being gentle with the butterfly. I know some people have said to not remove it, but others have been ok with removing it and cleaning.
Well after reassembly, started up the car, rpms were high hitting 2500-3000. Let it run for a few minutes, came down a bit but not much. I then tried to follow the GM relearn process, which did not work since the rpms are still high. It is coming down slowly, finally at idle the rpms drop below 1000, but when driving and when i lift my foot off gas pedal, the rpms remain the same as if my foot is on the gas. Car drives it self. Also putting in neutral and revving up, the rpms take a few seconds for it to come down.
Did the relearn a couple times last night and this morning and still the same. It is getting better slowly with idle rpms but when driving the rpms stay up there as if cruise control is enganged.

any ideas?
thanks

Oldblue

The OP stated it took a few weeks for the relearn, there was mention of the dealer to reflash the computer.
You might try a reset by disconnecting the battery neg cable for 30 minutes.

skyline26

yes sorry i forgot to mention that..i did dc the battery after the relearn process did not work for the first time.

Oldblue

Oh, so then it's a waiting or spending game!

donbrew

As far as I read the relearn process is simply idling for three minutes.

I have cleaned my TB several times, both on the car and off the car. I have never neede to do anything but start the engine and go.

Oldblue

Me either, Don, but some HHR's are picky.

skyline26

^^ yes thats what it is.
What i did:
1. Start car and let idle for 3mins
2. shut off car, wait 60 seconds
3. restart car and should be fine...nope! so i dc battery and re did the 2 previous steps. I then noticed that if it still doesnt want to relearn GM suggest doing the next step
4. run on highway with a few hard decels and accels and reach atleast 70 and coast.
5. shut off car. wait 60 seconds
6. starter her up again and a lot of waiting and finally idle came down to below 1000rpm compared to it being up around 1500.. but its when driving that it holds the high rpm

donbrew

I should add that I have also done it with the TB connected and disconnected and have never reset the computer in any way.

BTW, disconnecting the battery/or clearing codes routinely MAY cause damage to the cat. I have read that the OBD2 tests can stress the cat. I am not sure I believe it, since the cat efficiency test is supposed to run "up to 3 times every drive cycle" after all of the other tests have passed.

I am thinking air leaks. Just a thought though, no experience.