I have been getting random misfires lately on my l61 with the m62. Just reinstalled the blower, ran better than before, except there was a cylinder 3 misfire a few times. Removed the plugs, they were sooty, but i moved every plug over a cylinder. Then there was an occasional random misfire. I bought a set of NGK LTR7IX-11 plugs, not gapped (kept at the .042) and I havent gotten many misfires. So far only twice did I see a misfire, and they were both after a start up from a warm engine (first time was high heat with 142 degree iat haha). The first set of plugs I had in were NGK's LTR5GP platunum plugs, not gapped either (kept at the .038). It has been in the 30's in Ohio with some humidity. The car did not misfire at allll on stock tune, no blower. I checked the plug boots, and they looked great. Smaller gap or new boots or icm? Ideas?
verify your intake manifold gasket is 100% sealed. Ive had multiple misfire issues. Fixed them all after many hours of frustration. One was the intake manifold bolt broke off in the head, so the manifold sagged. Then the manifold gasket was crap, so i bought a new LSJ one and put it on. then one time I ended up pulling too hard on my fuel injector wires and one was seperated inside the wire...had to splice it back together.
misfires, first thing I do is spray carb/electrical parts cleaner all along the manifold. check for leaks and if it tries to die on you youve got a leak.
are you getting any codes?
04 Cav. 2dr. 5spd. My DD. 'Nuff said.
Thanks blu. I actually had my father come over to help witht the search for the issue, and thats when he smothered my intake and blower with carb cleaner, nothing happened.. And the gasket I have is a brand new LSJ one from GM parts direst with a layer of fresh rtv, and the PCV port has been cut out of the gasket as the GM instructions say to do. And thats what happened to me the first time with the wires!! I couldnt figure out what was wrong, then realized my splices came undone, so this time I soldered them. And I get a P0300, but witht the platinum injectors the first times, I was getting P0303. And there were no similiar readings during the misfires, some happened when cold, some when under boost, some when at idle, some with part throttle.