If you don't know what a misfire sounds like just turn your truck on, open your drivers door, put the truck in drive, put your foot on the brake, hit the gas and our drivers door should be vibrating like all hell (make sure it is still open). I'm sure you can find lots of pics of fouled out plugs on the Internet. If you haven't changed them in the last 30k, I would say it is worth doing anyway.
My new motor when i got it had a bad missfire for some reason.i was about to kill the guys that work at the shop who dropped in my new motor in my truck...literally..... , easy fix had a cracked spark plug...replaced it motor ran like a champ ever since.....if u have a miss fire trust me you will know because the motor will run like it ain't fireing on all 8.
I still don't understand what a misfire sounds like. If I powerbreak it with the door open I'll hear tires burning. Not rattling. I yanked a plug and it looks like its got a good deal of carbon on it, not wet with oil at all. The white part isn't white anymore, completely covered with carbon. Would this indicate a fouled plug?
a miss fire won't sound liek anything....on my truck just when u would rev the motor it acted like it was missing a beat....u say the plug was all carboned up....go ahead and replace um and see what happens can't hurt.
sounds right to me....u have headers???? grab each one of the header pipes by the head....if a cyclinder ain't fireing the pipe will be cold...if hot and burning fine the pipe should smoke your finger...LOL have fun....trust me it will work.....your'll know if all 8 are firing.