1999 Ford Truck 4.6 Liter engine idles fine

1999 FORD TRUCK
155,462 MILES • V8 • 4WD • AUTOMATIC
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LGRENDELL
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  • 1 POST
idles fine but when you put a load on it it seems to be cutting out . New plugs and wires. Tail pipe looks black inside. no check engine light.(unusual )
Jul 28, 2009 at 1:59 PM
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RASMATAZ
  • CAR REPAIR CONTRIBUTOR
  • 75,992 POSTS
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
Jul 28, 2009 at 2:08 PM
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