I recently helped a friend of mine with the following problem:
His check engine light would come on and the codes read would be related
to the O2 sensors.
He complained about the car having intermittent power loss but would not
describe it as a miss.
Last week the car finally died. The mechanic changed the fuel pump
($420 including parts and labor) to no avail and then suggested to
replace the computer. That is when my friend called me.
$16.95 for a month subscription to the online catalog led me to test the
crankshaft position sensor. When I looked at the sensor I found it to
be too far away from the tone ring.
Cleaning the sensor, and adjusting it's position solved all 3 problems.
The adjustment consists of getting the plastic tabs that protrude from
the sensor, to be almost in contact with the tone ring. In a new
sensor, as per ford, the tabs are left in contact with the tone ring and
the expected wear will give the needed clearance.
The problem is caused because the geniuses at ford, designed a rather
long plastic bracket for this sensor. With repeated heating and cooling
of the bracket, the plastic's differential shrinkage moves de sensor
away from the tone ring.
I hope this info helps and I apologize if this issue had been discussed
previously; i did not take the time to search the newsgroup.