05 F250 6.0 96K Miles, 1/4 throttle stumble

[scottg22]

Just wanted to pick your brains on my truck.

05 F250 96k and is all stock except for a MBRP Exhaust with no cat. Its pretty much ran ruff and hard to shift when cold for quite awhile. I usually let it warm up for a bit before driving it.

Recently, the truck has developed a stumble while driving say 40mph at 1/4 throttle. The truck stumbles then clears and u can see a puff of blue smoke in the passenger mirror.

stuck injector? Clogged EGR ?

Where to start to try and diagnose ?

TIA !

[04cr450]

Yes either a stuck injector or egr... Try pulling the egr valve and cleaning it first and see what happens.. If not go to the dealer and get them injectors tested on IDS.

[ZMANN]

Sounds like possible stiction what weight oil you running

[scottg22]

Valvoline Synthetic 5w40 since 30k miles Awhile back I ran some Rev-X (with no improvment to rough idle on cold start/blue smoke)