I have a 2005 lly allison, truck runs good at start-up but after temp reaches 185 deg. to 200 deg. at idle when in drive like at a stop light it begins to miss real bad and starts smoking from exhaust real bad. When temp comes up to 210 it all goes away. Also fuel mileage has dropped to about 10 to 11 mpg. I have had it to the dealer as it only has 21000 miles on it and is still under warranty, they said maff sensor was dirty so they replaced to no avail, so i took it back again and the said this time they got a egr code but they dont seem to know what's wrong. I changed fuel filter air-filter before taking to dealer first time. Anybody have any ideas so i can maybe give Mr. goodwrench a few suggestions? Thanks for any help.

Have them check injector balance rates.

They checked balance rates and they were all good. 5/17/06

Do you have the latest reflash?

dealer just called and told me they reflashed. I didn't know if that would fix or not?I guess when i pick it up this afternoon we will see. Thanks for all your help!!!!

Mine used to be real rough right when I stoped or if I tried to creep forward with some pressure on the brake. The reflash fixed it. There is a TSB on it somewhere.