Hey everyone, new to the forum but not to the problematic cobalts. Here's what I have going on: had a WARM idle miss on #4. Ran perfect off idle. Did a leakdown and it ended up being a burnt exhaust valve. I tore it down and sent the head out to be rebuilt and put it all back together, everything was all good for 1k miles or so. Now at a stop with the engine at operating temp you can feel a hard miss every once in awhile. No CELs and no miss history that was out of line on the scan tool. 120k miles. New plugs, fuel filter, timing set, tensioners, injectors pulled and flow tested, new coil, and ICM. Not losing any coolant and performance is perfect off idle. All pcv system was checked over. Any ideas what could be the problem? Maybe MAF? MAP?