So I’ve been dealing with a misfire for awhile now and can’t get to the bottom of it, it only happens at start up and when I come to a stop/idle other then that the car runs fine and strong. I’ve also changed out parts that may lead to a misfire like spark plugs, mass air flow sensor, camshaft sensor, coil packs, port injectors, and swapped the upstream o2 sensors to see if the code followed. Codes are P0316, P300, P0303 mostly, and sometimes P0302. I took the car to a reputable shop in...

Misfire issue