I have the same problem.
Simple things to look for:
Any metal contact to the the postive side of the battery or starter
bare plug wires
arching (look for that at night)
a little more invovled:
plugs
coil packs
Ingtion control modular (might as well replace the coils if it's that sicne you have to remove them
going bad MAF (ohm test it before replacing unless it's tripping the SES
Exhasut leak at the engine?
That is what I'm going to check in a few mintues. My headers are leaking pretty bad at 2, 4, and 6 and it's popping out the exhaust and I smell unburned fuel, really heavy, at the front (left side transverse engine) of the block. I also hear a ticking and it's driving me nuts!!!
I have the gaskets, but this just started last week. Time to get off my ass and DO IT!!
(I hate 2nd shift)