I am at a loss to isolate where my problem on this 5.3L engine.

I have an intermittent misfire occuring at idle that is not isolated to one cylinder. In fact there is no pattern that I can detect. We have checked the obvious, Plugs, Leads, spark, fuel injectors, O2 Sensors, compression ie everything you would normaly look at.

Need some help to point me in another direction. (Please)

 

Mine feels like it stumbles at an idle also, it could definetely be a misfire, but i haven't checked with autotap or anything yet, kinda makes me wonder, ecspecially since the friggin truck only has 9000 miles on it. I checked the mass air wires for K&N oil, none, was gonna wait and take it to the stealership just to pester them, since my interior pass. doors are squeaking still, after i had them look at it once already, and the said it was the dash surround piece squeaking because i put an aftermarket radio in it.............B.S.

 

i had a problem similar to this. ended up being bad plugs and wires. but here are some other possibilities:

fuel filter
IAC valve
leak in intake tube (around MAF or TB)
ignition coil bad
fuel injector clogged

 

I got that code this morning when I started her up funny thing was it didnt sound or feel like a misfire the code said random misfires on random cylinders?
Light went off later today and it drives fine???

 

I got that code as well. p0300. I talked to my tuner and he mention that some PCM's are sensitive to that code. I sent it back to him and he took care of it. I, as well, did not feel anything wrong with the truck, hell it has 11,000 miles on it.

Late

 

When did you install the cam?

 

After my wife kept driving while the truck continued to overheat the heads had to come off, (4 burned intake valves, most valve guides had warped, one injector, and most got plugs burned) but she remained focused and got to and from the mall! I thought if I have to build the top end, why not go ahead and drop in a cam. I hope to get the truck back today or monday and then I will be good to go again.

By the way, to any and all interested. My intermittent misfire was being caused by a bad catalitic converter. No codes were being thrown and my truck has not got alot of miles on it so a mechanic would not usually look in that direction.