1999 Ford F-250 Runs Ruff! No Hard Throttle Responce!

ROKARTIST

MEMBER
1999 FORD F-250

Engine Performance problem
1999 Ford F250 V8 Four Wheel Drive Automatic 96k miles

My 99 FORD F250 is not responding when I put the throttle down it actually slows down. How ever it runs ok if I ease the throttle / Also when I am going up hill it is worse and runs ruff. Also the PCM Fuse was blown and after changing it I had it tested at AutoZone and there indicator read no problem, so I put the throttle down and it acts as though it has no fuel and the auto lighting sensor was not working then I changed the 20A PCM Fuse and the auto head light sensor works and the check engine light went off yet it still runs the same! What Is Up?

1 Reply

RASMATAZ

MECHANIC
75,992 POSTS

Could be one of the following check and test

Oxygen sensor
Catalytic converter
Dirty fuel injectors (cleaning the injectors often fixes this).
Bad MAP (manifold absolute pressure) sensor
Bad TPS (throttle position) sensor
Bad or dirty MAF (mass airflow) sensor
Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
Bad gasoline (fuel contaminated with water or too much alcohol)

Sometimes, what feels like a hesitation is actually ignition misfire rather than lean misfire. The causes of ignition misfire may include:

Dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Wet plug wires
Cap and rotor