6.0 running bad-good bad- no codes or smk

[boisdarc1]

my 2003 6.0 is running terrible.
there are no codes and no smoke.
it sometimes runs great, then all of sudden, it just sounds like it is running on a couple of cyl. it will rev up but slowly and as if it is starved for fuel/air?

then it will go back to normal and all will be fine until it does it again. can last 5 minutes or 10minutes. at any speed.

anyone have any ideas before i start replacing parts?

thanks,

james

[Evil Eye]

I wouldn't just throw parts at it. Is it only when it is cold or a first start? Could just be stiction in the injectors, dirty EGR valve or that your turbo needs to be cleaned. Pull your EGR valve and clean it if you haven't done it in a while.

[boisdarc1]

hanks for your reply evil,
no it starts great sometimes. usually if i kill the engine when it is running poorly, it will not start. if i come back after an hour or so, it starts right up. as a side note, and i am not sure if it is related, but i did add diesel kleen (grey) and that is the day it started. could i have loosened up some crud and it is sporatically jamming the injectors? i have replaced fuel filters so far and did a really goood job cleaning my air filter.....i'll clean the egr valve and see what happens.

[boisdarc1]

confusing statement from my last post. after i added diesel kleen is when i started having the trouble.

[Evil Eye]

Keep us posted. Diesel kleen should help and not hurt performance.

[boisdarc1]

cleaned egr valve. still runs the same.
its weird. if i am going say 55 at 2000rpm and the engine starts it's little tricks again, it will stay roughly the same rpms and speed. just absolutely no power or acceleration. if i stop, it just takes forever to get to speed, but the rpms go up and down... just no power. makes no sense to me.