Well, you have to think of what goes on inside, you already eliminated the spark concept, but is it the correct gap setting and proper spark plug? That could be it as well.
What year is your cobalt? Do you have a Ignition module thats mounted on the spark plug cover? That could be a culprit too. I would highly doubt a PCM, cause its rare for just one code, generally a faulty PCM would cause multiple codes that have been corrected, but wont reset.
You also eliminated fuel, but you also have to remember timing is a concern too
Dont always assume the cheapest route is the fix unfortunately. I would highly suggest since you have a time restraint to get your emissions tested, to take it down to a dealer and at least pay the diag fee, at least they have the proper scan tool with the best solution to fix it. Their tech II will display if its a mechanical or electrical misfire.
2009 Cobalt LS XFE U74
Mods: K&N Typhoon Intake, Option Cat-Back Exhaust, Cosmo Short shifter, Maxxim Ahead 17X7's, MPx shorty antenna, FE5 Strut/shocks, Tein S Techs, Moog endlinks, Moog spring seaters, ZZP shorty header, LSJ downpipe, LNF front grille
Last edited by 5t3alth; 05-06-2014 at 05:05 PM.