02 Chevy 2500HD 6.0 Liter 4wd 111,000 miles
was driving down the road stopped and the truck was idling awful shaking like it was misfiring shut it off and read the codes. had 5 codes 1 was for the MAF sensor 2 were for the O2 sensor 1 was the knock sensor and the last one was for multiple/random misfires. I cleared them but shouldve wrote them down but i didnt.. started it back up hoping to get it home now it still throws the misfire code but not the other 4. truck has very little power and shakes a lot with the misfires i havent done anything yet dont want to just throw parts at it.
thanks for any help

 

Welcome to the forum...

I would start with the basics, removed and inspect air filter, check that no debris is in the intake hose and that the is clean...
Pull the spark plugs and inspect, if they have not been replaced its probably time to do so...
Check the spark plug wires, make sure they are all fully connected, if they are original consider replacing also..
Check the fuel pressure...

 

How do you check the fuel pressure? never done it before and i plan to do all the plugs wire filter and ill check the intake itself. Should i clean the MAF sensor? and the other thing i noticed was the tranny wasnt shifting well either is that like a limp mode kinda thing? Thanks for the advice

 

I have a 2003 Suburban 5.3L. I am having the same exact problem, multiple cylinder missfire only when idling. As soon as you hit the gas to take off it runs perfect on all 8 cylinders and No power loss. About a month ago it started bogging down and stalled out. Would start and barely run. Let it sit for 5 minutes and it would start and run fine for ever until you turned it off again. Always had to wait a few minutes before starting back up. I took a board and hit the gas tank a few times and it has ran perfect ever since. UNTIL NOW, I ran it to E one day and gas light came on, (I never do this) I filled gas tank up and when I started it back up it just started missing only on idle. I've done the following...new fuel filter , has new plugs, new wires, recently had knock sensor code, so I replaced those with wiring harness, and intake gasket...the missfire started before knock sensor code so fixing those did not fix idle missfire. symptoms are similar to when I had to hit the gas tank but no where as extreme and I don't know if letting the gas light come one was coincidence or not but the problem started as soon as gassed it back up.
So could running it to E have anything to do with it?

Would it more likely be fuel pump or pressure regulator. (I'm told fuel pumps usually completely quit, it's not gradual. however hitting the tank did fix the extreme want to stall )

coil packs or plugs (electrical items) would show worse symptoms under load not on idle.

if it was fuel injectors odds are it would be one not multiple all at the same time.

WHAT FUEL RELATED CAUSE COULD IT BE TO CAUSE RANDOM CYLINDERS TO MISS?

 

Had the same issue...I cleaned the throttle , replaced the fuel pressure regulator....no help. Finally found that one spark plug wire was not seated properly. That fixed the issue.