How do I know if my crank position synchronizer is bad on my 2002 F-150 because its not idling correctly.

FPIERCE

MEMBER
2002 FORD F-150
140,000 MILES

The engine light is on and the code came back with an 02 sensor I replaced it, didn't work. The reason why I think this is the issue is because a friend of mine was having the same issue with his truck and his mechanic replaced it. My friends truck runs fine now, so before I replace it I would like to know how to test it. It looks to be a pain to do. Thank you

4 Replies

KHLOW2008

MECHANIC
41,814 POSTS

What is the exact trouble code you are getting?
After replacement of the O2 sensor, is the trouble code the same?
Did you check the O2 sensor circuit?

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Saturday, February 4th, 2012 AT 2:42 PM

FPIERCE

MEMBER
1 POST

Ok I went to get the codes read here's what I got p1131 p1151 p0171 and p0174

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Saturday, February 4th, 2012 AT 5:18 PM

MHPAUTOS

MECHANIC
31,937 POSTS

P1131 O2 sensor not heating.
P1151 same as above
P0171 & P0174 lean mixture.

With all these codes I would be checking the air flow meter first.

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Sunday, February 5th, 2012 AT 12:56 AM

KHLOW2008

MECHANIC
41,814 POSTS

Did you test the O2 sensor circuit? When a sensor is replaced and it is not responding, it could be a open circuit instead of a faulty sensor.

Mhpautos is corrct about the MAF being a possible cause.

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Sunday, February 5th, 2012 AT 5:36 AM