Thread: p0301 keeps coming back

ok so i just did a lim gasket job on my dads car which has a l36 on first start up it smokes wich is normal as i had to burn off all the coolant it clears up and there is a slight missfire and i get p0301 so i replace the spark plug in cylender 1 problem gone i take it for a test drive like to the end of the block and back and it comes back with a p0301 and is missfireing again what is the problem

just started after the LIM job? i doubt this is it, but you could diagnose the coil packs by switching the one for cylinder 1 with another one, and seeing if the misfire moves to that different cylinder.

problem solved bad plug wire