Car Hesistation

1995 MERCURY COUGAR
53 MILES • V8 • 2WD • AUTOMATIC
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SAMTHEMAN
  • MEMBER
  • 31 POSTS
I had a bad misfire for about 2 months, I changed the plug wires and that fixed it.

Now I have a problem with hesitation on acceleration as well as rpm dropping down to 1k rpms while the engine is under load. Note: this only happens when the car is warm, when it is cold it is fine.

Also the cars idle after its warmed up stumbles a little bit.

Things I've Changed:
fuel filter
spark plug
spark plug wires
air filter

Any idea what could cause this?


Thanks.
Jan 30, 2011 at 7:12 PM
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RASMATAZ
  • ✓Experienced Mechanic
  • 75,988 POSTS
Could be caused by one of the following below

Oxygen sensor.
Catalytic converter.
Fuel injectors dirty/sticking.
Mass airflow sensor/Airflow meter.
Throttle position sensor.
Crankshaft position sensor
Knock sensor
Manifold absolute pressure sensor.
EGR Valve
Fuel pressure regulator leaking or defective fuel pump.
False air leakage.
Fuel contamination.
Foul/defective spark plugs.
Open spark plug wires.
Ignition coil/Coil packs defective.
Incorrect ignition timing.
Cap and rotor.

Note:If it doesn't apply disregard it and keep testing.
Jan 30, 2011 at 7:14 PM
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