2001 Ford Focus lumpy tickover, missfire.

BRIAN.KVN

MEMBER
2001 FORD FOCUS
4 CYL
FWD
MANUAL
79,000 MILES

My car developed a misfire on tickover and a week or two later the engine managment light came on. I took the car to a ford dealership and they diagnosed the problem as a faulty PCM(ECU) which would need completely replacing. I could not afford to have the PCM replaced so I went to another garage which sent the unit off for a rebuild. They also changed the plugs and replaced the coil pack. Despite having this work done the problem still exists. I have since taken the car to three different garages without any success of getting the problem resolved.

Wednesday, August 12th, 2009 AT 8:28 AM

1 Reply

SCHRIMPIEMAN

MECHANIC
166 POSTS

Being that you've had the ignition side of things replaced with no success, try the trigger side.

What I mean by "Trigger Side":
The PCM may not be getting a clean signal of when to tell the coils and plugs to fire. Inspect the crankshaft position sensor and the Crankshaft pulley.

The pulley has the serpentine belt riding on it; in back of the pulley is a ring with teeth on it. Inspect the teeth very carefully to make sure there is no debris or teeth are not bent out of alignment. If pulley/teeth check out Okay, you may want to consider changing the crankshaft position sensor. They're available aftermarket for about $30. The sensor "reads" the teeth of the crank, and sends signals to the PCM. Sensor is located at about the 10:00 positon, viewing main pulley thru the wheel-well.

Access is limited, but possible.

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Saturday, August 22nd, 2009 AT 8:34 PM