Hi everyone! I bought a 1999 f350 v10 about a month ago took it on a 1200 mile trip from Arizona to Kansas. Truck ran great till I got Kansas. The truck started to lope after I got fuel at a fuel station. Did not get any check engine light on. I check for vacuum leaks did not find any. I change all the coil packs, spark plugs, IAC valve and fuel filter. Clean the intake and put sea foam in the fuel tank and the truck still idles rough. Change the egr vavle. Truck ran great till I got 10 miles down the road then the truck started to lope again. So I'm getting really frustrated over this truck and looking for some help!

 

You didn't wash the top of the engine by chance did you?

 

maybe crappy fuel? might have semi-plugged the fuel filter?

 

No but when I was driving I traveled through a brunch of rainstorms for long periods of time. Is there another fuel filter located some where else on the truck?

 

No, if the top of the engine gets wet, it can sometimes cause havoc with the high tension side of the ignition system.