I have a 1991 Ford F-250 300 i6 with a five speed manual. When starting it up for the first time of the day the engine spits and sputters until I hit the foot feet and then it levels out.

Also, once the engine levels out and the engine reaches close to operating temperature the truck starts to get sluggish and feel a loss of power while accelerating. The warmer the engine the worse it runs. Burns no oil but when idling seems to overload on fuel and then starts to miss and cut out. Truck has 205,000 miles.

What I have done trying to fix problem:
replace ignition control module
plugs and wires
new distributor cap and rotor
fuel filter
cleaned mass air flow sensor
compression test(all cylinders around 140 psi)
fuel pressure
Replaced cat and new exhaust mufflers

Does anyone have any other ideas of what to do? Any and all help will be greatly appreciated

 

if fuel pressure is between 45-60psi, engine running, then i would pull codes and check for vacuum leaks ... in that order.

 

And if that all checks out I would drop the exh head pipe before the cats and take it for a quick test run.
My thinking is plugged cat(s) and or muffler and why I said before cat(s).
If it has power again then it is either plugged cat or they came a part and plugged the muffler.
Dave ----