Having some major trouble figuring this out and so are mechanic shops. I have am 03 F250 CC SB 125,800 on it. Only mod is a straight pipe 3 1/2 inch exhaust. I am having some odd problems with it. To start it off, when i am in final gear around 1400-2000 rpms it shakes really bad. only in final gear. rarely will put out white smoke, rarely will give me a hot no start. fires up fine when cold, runs like crap when cold. when warmed up runs fine. have a small oil leak from back of engine. looks like a main seal. when i let it run for a couple minutes then take off if rushed for work it feels like i am pulling a house behind the truck. lags and sputters alot. but when warm runs fine. FICM tested and checked out perfectly fine. Scanner at a shop said i have no misfires so injectors should be fine. there was a pressure that was running 4400 on their scanner and they said it should be at 5000. i just can't remember what it was. Their guess is HPOP or IPR. but they are unsure. Does anyone have any guesses as to what it could be? I am lost and stumped by this and getting really stressed out.

 

I go for IPR, almost sound like my 6.0L but your not throwing codes so my next guess would be the IPR. Im not sure what the Pressure should be for the HPOP but IPR has alot to do with injectors. On second though!!! haha! We had an 7.3L acting like that when it was cold it would be a dog to go then when it warmed up it did well we change out the IPR and wallaa!!! runs great!!!! your gonna need a metric crow foot to get er out though. If you know anyone else with a 6.0L PS i steal theirs and try it and see if it runs good before you spend the bucks for and IPR...

 

Okay so, my guess is IPR or FICM because FICM's can show perfect and still be crap. your cold start issues lead me to believe FICM and your oil leak leads me to believe IPR. Do you have another truck to swap the FICM with?

 

You tried Rev-X like we suggested right????????

Shaking at speed is typically sticking injectors. Does this issue go away when warm?

 

The oil leak is most likely a bad ICP sensor on your 03, they are known to leak and when they do it messes up the readings, can cause cold start problems and can even cause it to stall, like at a stop sighn or even backing out of a parking spot. they leak so bad they even give you a new pigtail because the oil will impregnate the connection and even the wire.

The oil leak is almost always the ICP on 03 and early 04 trucks......................