Hello, I have a 2006 HHR with 220K miles, it has been extremely reliable, recently my MPGs had dropped some and I had a slight rough idle so i changed my air filter because it was due and I changed my spark plugs because I couldn't remember when they were replaced last and figured that was the cause of my issues. With the repairs done I started the car and it idled perfect but always idled well when cold so I drove around about 4 miles everything was perfect. Later that night I drove about 5 miles and was on the interstate and floored it to make a pass as usual it down shifted and took off, pass made I resumed normal speed and felt a little hesitation, I took the next exit and when I let off the throttle the car started to buck and the CEL came on, stopped at the stop light the idle was all over the place and the car shuttered, the TC light came on, and as I pulled away the reduced power light came on. I pulled over and checked codes P0068, 0101, 0106, 0300, I cleared the codes restarted the car and headed back home, about a mile later it happened again, cleared the codes ad restarted the car, it ran a little rough and felt unresponsive then all of a sudden it took off and ran perfect. About 2 miles later I stopped at a stoplight and the idle was perfect, a mile later CEL and power reduced back on, reset and made it home. Google search suggested cleaning the TB, this made since to me with the high miles, cleaned TB with carb cleaner and moved the butterfly with my hand, restarted idled was rough for a minute then smoothed out, put it in reverse and i felt the RPMs go a little high, driving the RPMs stayed around 1500, drove about 4 miles and CEL back on, got home and put it in park and the idle went to 3250, CEL code was P0121. Thinking the TB was the HHR weak point and it has 220K on it I replaced the TB. Now in park it idles at 3250 RPM and in drive it will come down to about 1250 and is smooth, with my foot off thr pedal it cruises about 35 MPH and will surge sometimes. I drove around today for 2 hours stop and go on a road with a 45 MPH limit stopping about every 20 minutes shutting down and restarting. No change, with the car off and the ignition on my OBD reader shows the TPS fluctuating between 23% and 34% one or the other up and down, with the car running it holds 34% in park. Any help would be appreciated, retired and would like to stay out of the dealership if possible

 

never use carb cleaner on a non-carburetted engine. It's designed to leave a film of oil, which will foul your sensors. Use intake cleaner.


OEM?
Did you perform a throttle re-learn with a diagnostic tool?



With all those faults for different sensors, I would suspect electrical issues rather than the TB itself.

 

Thank you for your help, it is much appreciated!! I had the high 3250 RPM idle before I cleaned the TB and after cleaning there was no change so I replaced the TB after learning the HHR TB can be a week link and mine has 220K miles on it. No I have not tried a re-learn procedure, my local Chevrolet service department has told me there is no such program. I have checked the connector at the TB and do not see any broken or dislodged wires, I agree it seems to be an electrical issue telling my TB to open, other than the high idle the motor runs perfect. I will try another dealer, thank you again for your help.

 

your local Chevy are idiots.