2000 5.3 with a miss. Need Help.

[396 SS]

I have already put new plugs and wires, new fuel filter. The code is showing random missfire. I checked fuel pressure and it is showing only 47 psi when it should be 55-62 psi. Will this cause a missfire?

[Huck]

Doubt it. with new plugs and wires---I would try swapping out each coil with a new one till you find the mis. Did any of the plugs show a different color? I would also try some injection cleaner with your gas. There is a lot of crappy gas out there these days and that can drive you nuts. Does the mis happen at idle, under load, or ?

[71 super]

My 5.3 showed misfire it was a coil, code should show number that is misfiring and the bank it is on driver side bank 1 pass. bank 2; 1-4 on each side if I remember correctly but not sure on the numbering system for the cylinders.

[396 SS]

I have run two bottles of injecter cleaner, with no change. It misses the worst at lower rpm under load . It was showing random missfire which he said was 6 or more cylinders.

[droppedgmc]

check your maf or o2 sensors...i've seen it cause that on those trucks(mine)