i have a cylinder 2 misfire in my pontiac grand prix gt 2004 i started out with the cheapest way starting with the spark plugs. it seemed to work fine for a good month than the check engine light came on again and the whole dash board started flickering, engine is running a little rough. Any of you have an idea what to do?

?????? Is this motor in a Fiero otherwise you are on the wrong forum.

[This message has been edited by IMSA GT (edited 02-08-2014).]

Scan it for codes, could be completely unrelated.

Scan for codes. Could be a bad coil pack or bad plug wire. I had the coil go bad on the 98 GTP swap in my dads car and then on the way to the parts store a coil went on my 2000 GTP daily driver. Moral of the story....coils go bad. Thankfully not expensive to fix and usually cause a code.

If that's the only code that comes up, then it's more than likely the coil. It's best to replace the wire at the same time.
You can test it by swapping the possible defective coil with a known good one, then the misfire should appear on the other cyl. Then you know for sure.
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[This message has been edited by Custom2M4 (edited 02-09-2014).]