HELP PLEASE ! Misfire on Cylinder 2 Code P0302 - Chevy Cobalt Forum / Cobalt Reviews / Cobalt SS / Cobalt Parts
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post #1 of 3 (permalink) Old 05-05-2014, 11:30 PM Thread Starter
Join Date: Oct 2013
Posts: 3
HELP PLEASE ! Misfire on Cylinder 2 Code P0302

I have been driving with this check engine light for months now
When I first got the check engine code I cleaned the valves, replaced the battery, spark plugs, ignition boot, fuel injectors and and even the fuel pump (due to it failed on me).
I basically gave up on spending money on anything else. I took it to a mechanic once he said it's the spark plugs, they changed it, Check engine light came back on a few days later.
I looked and looked online IDK what else to look for. Is it possible that the PCM is messed up?
I've been driving for months with the code on, misfire can be felt at idle but driving is perfect, no problems. HELP

---------- Post added at 10:28 PM ---------- Previous post was at 10:28 PM ----------

I also did a compression test it was around 120psi, seems good. No lost of coolant either

---------- Post added at 10:30 PM ---------- Previous post was at 10:28 PM ----------

Smog check coming up in a week, I need help lol
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post #2 of 3 (permalink) Old 05-06-2014, 05:03 PM
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Join Date: Jun 2011
Location: Charlotte, NC
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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.
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post #3 of 3 (permalink) Old 05-07-2014, 05:20 PM
Join Date: Mar 2014
Location: Ottawa, Canada
Posts: 39
what does your sparkplug look like? Here is a chart:

What do you mean you cleaned the valves??
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