New 04 hemi owner, had GM's for 25 years, love the truck, great ride, 45,000 miles gray, quad, service shows, had tune up in March 09, cleaned throttle body, owner stated misfire. I am running 89 midgrade name brand fuel, had one month started missing some, check engine light, took in to dealer, they showed misfire in history, but nothing going on then. ??? Said might need rack cleaned, or wet fuel, been thru couple of tanks and still missing around 55mph, any help here.
Gracious
Cromag! Oil field Trash for 30 years.

 

Welcome to DF! Now when you say Tune up you mean the plugs were changed? The plugs should be changed every 30K miles. 89 octane gas is what you should be running. If the plugs havn't been changed I would put a fresh set of Champion coppers or NGK's in and it wouldn't hurt to run some Fuel system cleaner through a tank of gas. Lucas is good or marvel mystery oil. if that doesn't fix it then you may have a coil pack bad. Does the code say where the misfire is? I would also pull the Neg. battery cable and reset the PCM to clear the memory. hope this helped.

 

Thanks for the kick, yes they (dealership) had replaced plugs,don't know hwat kind, did put lucas in , long time user, will do the neg. cable trick. work offshore Gulf and lots of interstate miles, does great around 75, will see how she goes. Was looking into the extended warrenty, seems to me these beast are pretty much trouble free for the first 100,00 miles? $2000 for another 50 g , think I'll trust the truck!! This thing has the quietest ride I've been in for a truck!
Bayou!