Ok so I have a really weird problem, and cannot find anything anywere on it. My car is almost back to stock, 2006 cobalt ss/sc, stock pulley and my old stock injectors, intake and full header back vibrant exhaust no cat. Now if I run the car in open loop fuel looks good. If I run the car in closed loop with the fuel trims workin it runs lean (according to my aem wideband, and idle is terrible) I have checked for a leak somewhere, nothing, changed out both o2s, cleaned maf and map, and nothing. I have done everything with tuning you can do (maf scaling, ve variations, timing, so on and so forth).

I decided to add this to problems service and maintinance. I really dont know if its a tuning issue or if its something that needs replaced (ie sensor or something). I will also mention there are no codes at all, and sometimes it will idle perfectly, and it idles perfectly at completely random times. I also have cleaned my maf and map sensors.

If in open loop it doesn't really fluxuate much just running off of the maf, sooooooo, not so sure where to begin here.