Mechanics

CHECK ENGINE LIGHT

1999 Ford Expedition • 4WD Automatic • 320,000 miles

Have a 1999 ford expedition, code 171 & 174 have been read on my OBD 2 scanner. What do has to be checked or replaced to erase these codes?
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Chester&Charlie
April 3, 2011.




02 sensors are reading lean, but with that many miles the should be replaced. Also check for vacuum leaks at the pcv rubber elbow its a known leaker.

Merlin2021
Apr 3, 2011.


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