Alright my buddy's GF's 2000 or so Cavi with the 2.2L has been acting up and throwing a CEL. He had it scanned and came up with a #3 misfire. He replaced the plug, wire, and coil pack. The problem went away for a while, (couple weeks I believe) then the CEL came back. Shows a #4 misfire now, so he replaced that plug, wire, and coil pack, but the problem is still there. WTF is going on? Some douche at the local auto parts store said the same thing happened to his and it was a MAP sensor. Does that like a possibility to anyone? Thanks!!!
i think it may be one of two things. replace the other two plugs and wires since sometimes the porecelin can crack and lead to a direct ground to the head, electricity always flows to the path of least resistance. so all the juice goes to ground instead of igniting the a/f mix although since it's a 2000 (SFI) i'm not sure if it still fires two plugs at the same time also known as the waste spark system.
another thing may be the head gasket, this can be verified with a dry compression test, then a wet compression test to see what the rings may be doing.
i've never seen a map do that, but there is a first time for everything.
