engine lights are on they told me to change the knock sensor, however the parts store gave me the egr sensor?
Ford Q&AAsk Your Question
1999 Ford Explorer Question: engine codes p0171 p0174 p0325 p1000
Answer #1DaveJHM May 07, 2011, 23:59Master
P0171 and P0174 are lean fuel codes - P0325 is a knock sensor code. Ignore the P0325 for now, as it may be related to the fuel issue.
Look for vacuum leaks with the lean codes. Specifically - on this engine - if it's the SOHC 4.0L V6 - it is notorious for failure of the intake manifold o-ring gaskets. I would guess that the leak is there.