1999 Pontiac Sunfire Repair Question
Multiport Misfire 1999 sunfire
Answer
I don't know where to begin since there can be many different causes for misfires. Suspecting the spark plugs, wires and coil is a good start. Since you don't have any other error codes this can narrow it down a bit. Does your car have a rotor and cap.
this is also a good possible reason. Dirty injectors or low fuel pressure can also cause misfires. A vacuum leak can also cause misfires. And finally low compression due to leaking head gasket, burned valves, worn valve springs, or worn cam lobes. Good luck hope this helps. Backyardmechanic :)
I had this same problem on my 2000 Grand Am 2.4L
It turned out I had a bad coil pack cover when the engine got hot it would arch through the coil pack cover and number 2 & 3 cylinder would not fire. I am not sure if the 2.2L has the same setup. If it does look at the coil pack cover and if it looks black through the bottom of the cover where the coil pack leads run to the spark plug boot ends I would replace the coil pack cover. Good Luck
I just spent several hours and replaced both coil packs and coil houseing along with plugs and plug boots did not solve the problem i got lucky while looking at the fuel rail i discovered that the fuel regulator was leaking fuel right into the
throttle body replaced it and it runs great and no misfire