ive heard conflicting info on this and have stuck with the stock plugs with various gaps anywhere from .030 all the way to .050 with and without the msd and I still get the 0300 misfire code im specifically interested in the NGK or Denso or the autolite 103s
1989 Turbo Trans Am #82, 2007 Cobalt SS G85
I am using the stock plugs gaped at .045 no miss fire codes. i have had the plugs out a few times to check them no signs of over heating.
Thats Him Officer The WICKED One.
autolite 103's..gapped at what my stocked one's were gapped when i took them out.
gapped @ .060 No missfire code yet. 10k miles @ only 5 PSI non intercooled.
i currently have stock plugs (ac delco) in it which i replaced when i got boost ive tried gaps anywhere between anywhere from .030 all the way to .050 and its always a problem, im thinking maybe i need a different type of plug i dismissed it as a possiblity in the past but im open to any options to solve this code 300 random/multiple misfire
1989 Turbo Trans Am #82, 2007 Cobalt SS G85
103s gapped at .025. get rich misfire codes 85% of the time when i make a quarter mile pass. the stock ignition is no good above 4200RPM at 10PSI or higher. Just cant keep up. PERIOD.
I used to race cars, now I race myself.
5K PB: 24:50
10K PB: 54:26
hmm maybe its time for the msd programmable
1989 Turbo Trans Am #82, 2007 Cobalt SS G85
Stock plugs gapped somewhere around .032. No misfire codes at all.
In my case......NGK TR6's (4177) gapped at .032 = No missfire codes anywhere from 5psi to 12psi. When gapped at .035 I had multiple cylinder misfires. I find it interesting some people have the gap as large as .060 I thought the boost pressure would blow the spark out.
I have an msd on now so i do have a stonger spark, how can one tell if its getting blown out
1989 Turbo Trans Am #82, 2007 Cobalt SS G85
it probly is not getting blown out if youre running lean...
LE61T PTE6262 Powered 
whats the proper ngk irriduim plug part # for the eco
1989 Turbo Trans Am #82, 2007 Cobalt SS G85
