I am new to the ecotec world and purchased a 03 cavalier with a manual transmission it is throwing a misfire code which is a given with my issue but the car will NOT idle for about the first 15 minutes of driving it after that it clears right up. It will sometimes idle rough with the AC off but won't even think about it with the AC on (I've just attributed that to the extra load on the engine.) I am more then capable of making the repairs myself no matter how major I am just completely stumped on what the cause is. I've heard everything from injector o rings to IAC valves just searching the forums. Any help would be greatly appreciated.

could be a very small air leak after the TB. id remove the intake mani and just make sure the gasket from mani to block isnt super flat or damaged and also the gasket from the mani to TB.

on the 2.4L im working on; i had a similar issue and it was the intake gasket from mani to block.

I'll look into that I appreciate the advice. The only thing that boggles me is that the problem will correct itself temporarily by leaving the ground to the battery for about 15 mins.

sounds to me like a vacuum leak, spray the car down with brake clean or throttle body cleaner around intake to check for possible vacuum leaks.

I have read on another forum that the ecotec has a different pcv system then most cars have and I know that there is a light am mount of oil coming out the breather tube could a vacuum leak cause that as well? Or would the port behind the intake manifold be a more likely scenario do you think?