Every time I start my car it has a misfire and goes into engine power reduce mode. When I delet the CEL it stays off for a few seconds then comes on again and goes back to engine power reduce. It does this until im at operating temp and then runs completely fine... Im going to change my spark plugs today but if anyone else might have some info it would be greatly appreciated.

 

I only had the engine power reduced mode kick in on me 1 time. But I found out it was my throttle body. I tried to clean it, code still came on. I replaced it and problem solved. Might not be your throttle body but I would check it in the process.

 

Yeah for sure start by cleaning the throttle body.

Other than that a code would help.

 

throws a p2135 I bought a throttle body off a member here but I definately got screwed on that because it had a slight rattle on the inside and I think thats what it is

 

gmpartsdirect.com sells you oem GM parts at basically dealer cost. check them out 1st b4 buying from anywhere or anyone else.

 

I had this same problem and it turned out to be my cat was bad. So I had it replaced

 

well I dont have a cat anymore so its not that. Im almost positive the throttle body I picked up was shot and now its just completely done. It just keeps throwing the code until im at 170 degrees then it doesnt come on anymore and the car runs fine