OK, got the rear mount back on the 8.1l today. Went great, drove it for about 2 hours on about 4lbs of boost. Then just easily pulling out of the parking lot, it starts shuttering real bad, then my SES light starts flashing. Checked it and says:
P0300 Random/Multiple Cly Missfire

What has caused this? Now it shutters the whole time and I can clear the code but as soon as I barley try to take of, it comes back. Seems to drive fine other than the shutter. Its like its missing on a cylinder or two. What should I check first? What is the worst case scenario?

 

if this is a recent install check for cracked spark plugs or damaged wires.

 

It is, I just installed it today, but Ive had it on in the past and never had this problem. I have NGK TR6's in it, but they probably have 20k on them. If it was just one cyclinder, would the code read that it was one cylinder?

 

what are the plugs gapped at? i had a cylinder misfire but it said what bank it was in , all mine was , was a fried plug wire but the obx headers are notorious for that.

 

.45 ...

 

hmm i think that is a lil too big of a gap . i was told to gap them at .32 for boosted aps. because the boost will blow the spark out... just what i was told .

 

hmmm, ok. I'll probably replace them 2morrow. So is it a GOOD chance its just some spark issues? I just let it cool off for a few hours and went out and started it again, it still doing the same thing.

 

thats what it sounds like, i would start there at least and check all wires and plug connections.

 

ok, will do. Im just scared shittless that ive messed something up bad

 

well theres no sounds or anything you can hear that is wrong ?