Heyo I just recently was in a accident on the 29th leading to me having to panic buying a car and I happened to pickup a cobalt ss 2006 with a perfect idle and working heat so I said **** it. Now after trying to do some preventative work on the engine since it's at 200,000km and now my idle is being super wonky on open loop but fine on closed along with the battery dying a few days ago so to a goof up on my part the electrical is being super odd. Full list of things I've done. Pulled throttle body to clean, ran injector cleaner, changed air intake plastics that sit in the throttle body do to old one being modified for a shitty cold air intake that didn't work well, along with full stock air box being reinstalled with stock maf, from said cold air intake. I know the engine was never re tuned for the cold air so I tired 6 idle retrains with a ecu wipe each time it didn't work (ECU wiping by shorting the cables separated from the battery) and that fixed closed loop idle but open loop keeps jumping to 1.5 to 2k rmp because the maf is reading .01 except when I give it gas making me believe that the maf is bad or there's a vacuum leak after the throttle body do to shitty install on my part. Regarding the battery and the not starting that has begone tonight I believe is a mix or battery just being dead, stock terminals not making good contact, (which I plan to replace tomorrow, or worst of all the classic cobalt gm ignition issues do to weight on the keys. The previous owner also wired in aftermarket subs like a **** head then took his amp but not the drivers or head unit so I worrie there's a drainage happening that idk about. Incase anyone is curious how the battery died to begin with it was do to me leaving the key in the ignition and the doors locking while I was at work so battery drained the the ECU went into a soft lock that I was able to undo by getting a jumpstart from a larger vehicle then clearing codes then starting car and the alternator seemed to have charged it because I got 20 good starts after that then only now it just won't. Going to replace battery tomorrow but idk what to do regarding the shity open loop idle any suggestions would be amazing.

 

It sounds like you’ve done a lot of work already, but with the open loop idle jumping and MAF reading near zero, a faulty or dirty MAF sensor is a likely culprit. Double-check all vacuum connections around the throttle body too. Replacing the battery and cleaning terminals is a good first step before digging deeper.