Ok, this is REALLY getting on my nerves! I've replaced the opti twice, new plugs, wires, header gaskets and the car runs great.... Most of the time.....however, every so often the car runs like complete crap! It'll backfire and run really rough, like its only on 4-5 cylinders. The next day, you can start it up and it runs great! Maybe even for a whole week. Its just nuts! The SES light hasn't come on and I scanned the car just for the hell of it and there are no stored codes. Does anyone have any idea what the problem may be? I know it should throw a code but could it be the O2's? If so, using datamaster, what should the normal range of the O2's be?


Thanks for any help!