Jasonpl3

I have a 2003 f-250 5.4 liter. My buddy put a little diesel into the truck, not alot but enough to slow his ride home from work. We have since drained the tank, replaced the fuel filter and out 20 gallons of fresh 89 in, with injector cleaner. This is where it gets tricky, the truck fires up great, sounds good, everything firing great. But after it warms up a bit, it begins to cut out, not when idling but when you rev past about 2000 rpm's. I can ease the throttle up to 4 or 5 k rpms, but if i slamm on the gas it just does nothing, just backfires a bit and chuggs.
Its a real weird problem, we also replace all 3 O2 sensors, but nothing changed.
When you let the truck cool down, you can start it and rev it fine, no probs, but as soon as it warms up a bit, you cannot rev it to fast or else it just chuggs alot.
Any ideas, i thought fuel pump maybe but those usually just die. We also thought spark plugs but i didnt think it would idle and rev so nice in the beggininng.
All help would be much appreciated.

thanks ahead of time!!

 

360ci

Change the fuel filter and plugs. Run a few more high end fuel injector cleaners through the vehicle and you should notice a difference above 2K. Be sure to run the fuel injector cleaners when you're low on fuel for best effectiveness.

__________________
'99 Taurus 3.0L 2V Vulcan 145hp; 107,820m
'00 Durango R/T 360ci 300hp (modded); 90,651m
'06 Pontiac G6 GT 3.5L 220hp; 14,224m

Amsoil in all vehicles!

ymeski56

The fact that the rpm's are available prior to reaching oper. temp.(195F) it's not a fuel delivery sys. disfunction, or Intake air, or Ignition system per say. Pre
195F, the engine operates with a slightly enriched air/fuel ratio w/ timing directlly correlated w/rpm only . The problem is after norm. op. temp. is reached, the PCM attempts to enter closed loop function and takes readings from the 3 O2 sensors and tries to retune to rectify for those readings. Problem is it is unaware it's been slipped a "Deisel Mickey" contamination. How much gas was in the tank when the deisel was added? How much diesel was added? How far was it driven? What's the CEL light &/or Emissions light behavior?