P306 cylinder 6 misfire

[swilki]

i have a 2000 chevrolet 1500 5.3L. The truck has a rough idle and has no power on acceleration. Code reads as a misfire on cylinder 6. i have replaced all plugs, wires, and coil on the cylinder. What else can cause the misfire?

[gjwickline]

you should check the intake for a vaccum leak on the #6 runner they are pron to leak. i have a 2003 w/5.3 had to replace intake for rough idle, hesitation. and fuel injector bad or dirty can cause miss also

[swilki]

I have read other responses similar to this one in other places as well. i will deffenately look into these suggestions. There is a second code now picked up, P0430 - catalyst system efficiency below threshold (bank 2), is this in any way affecting the misfire?

[gjwickline]

this wont cause a miss fire. the miss could cause the catalist code especialy if your intake is leaking vacum, an exahust leak will set the catalist code as well. you should repair the cause of the miss fire and then consintrate on the cat, code if i still returns. miss fires if left un repaired can ruin the cats.