i have been trying to diagnose my p0300 code for a few days here and its starting to drive me nuts. the truck is a 1999 silverado 1500 4.8l, no mods. for the most part it seems to run fairly smooth, the biggest symptom is that when it's cold, while trying to accelerate from a stop i get a bit of a stumble and sometimes it will "pop" through the intake or exhaust. it has new plugs, new wires, 3 new 02 sensors, a new maf, and new intake gaskets. i checked on the scan too and is seems that #8 cylinder is misfiring fairly often although i cant feel it most of the time. i've tried swapping coils, wires and plugs and the miss doesnt follow. i also put a stethoscope up to the injector and i can hear it ticking.... im running out of ideas, im thinking either a bad injector or possible valve issue... any input would be greatly appreciated!

 

no takers??

i did a compression test and everything looks good.... i guess i'll try swapping injectors next

 

my bet would be ur number 8 injector, i just cleaned mine out wit solvent an they worked fine

 

thanks for the reply...i'll give it a try

 

no problem let me no how its goes, just remember to take the oil rings off or the solvent with mess with them