1998 Ford F-150 Engine hesitates/Jumps while cruise is set

BKLUEVER

MEMBER
1998 FORD F-150
V8
4WD
AUTOMATIC
142,750 MILES

While my cruise is set, the RPM's hover from 1500 to 2000. It is like the truck thinks it needs to work harder so it revs, and then slows off. It doesn't do it all the time, but it does do it a lot. Is this an engine problem, a transmission problem, or just something that happens with age and mileage? If I were to put a new performance air filter in the truck (like a K&N) would that help the problem?

Monday, January 11th, 2010 AT 7:19 PM

1 Reply

RASMATAZ

MECHANIC
75,992 POSTS

Check and test the following below:

Oygen Sensor
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

Note:If it doesn't apply, disregard.

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Monday, January 11th, 2010 AT 8:07 PM