so ive been having this prob for a few weeks now, it happened right after i did a seafoam treatment, but i suspected water in the fuel, it ran rough at first startup and around 1500 rpm cold, once warm it was fine, 2 tanks later and 2 bottles of lucas fuel injector cleaner and shes golden even has alot of her power back too! but today it misfired n 2nd going up a hill at 1500 rpms, jumped between 1500 and 1700 and i got a MIL i havent had a chance to get it read yet but im suspecting just a misfire code, ive also checked and cleaned the TB, checked plugs for fouling and they look good, anything thoughts on what els it might be? also this is an 04' 2500 5.7 auto thanks guys

 

Coil or plug wire breaking down under load.

 

well the plug wires are new, but the boots under the coil are old , could this be the culprit?

 

I've seen it happen on Ford COP's, I'm sure it could happen on the Dodge too.

 

Something you may want to check too, is that you don't have any moisture in the chambers where your spark plugs screw in. Sometimes that'll make it spark out and cause a misfire code to show up. This happens to me sometimes when I wash my truck with a pressure sprayer.

 

k, thanks guys ill look into it, prolly replace my coil boots and check for engine grounds n such, let ya know what the code is here in a few

 

Be sure to put dielectric grease on the boots as well!!