OK so I have an 05 tahoe 4.8, Started throwing a Missfire P0300 Code and stubling at idle and clearly not running on all Cylinders, I cleared the code and ran good again for about 20min, I Replaced the camshaft Pos sensor, Mas air flow sensor, Intake manifold gaskets, Checked fuel Pressure, Checked for Vacuum leaks, and still doing it.. But wont always do it.. thought i fixed it after the Cam shaft pos sensor took it for a 20mile cruise felt good.. parked it for the night started it in the a.m and back to it... It throws the codes faster when the AC is on but assuming thats just because its asking for more power... Its also throwing a P0480 Cooling circuit 1 code and that fans coming on randomly at night and killing the battery, idk if its related, but all started.at the same time... HELPPPP ME IM STUMPEDDDD

 

does your scan tool have the ability to view the misfire counters. this data will tell you which cylinders the misfires are accumulating on. then you focus on that cylinder.

 

it doesn't.... I was up till Midnight last night doing my final nitch effort of the Crank pos sensor just to have it still be messed up.. so I gave in amd took it to a GM certified shop this morning to figure out what the heck is going on...