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Q:

PO 171 CHANGE O2 UPSTREAM AND CHANGE THE MAF SENCER CHECKED VACUUM LINES on 2002 Ford Explorer

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EXPLORER RUN GOOD MAYBE GAS CAP, OR RE CHECK VACUUM LINES,SHOULD I CHANGE THE DOWN STREAM O2 SENCER, PLEASE HELP
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(4) Comments
171 is bank 1 vacuum leak. it is not the o2, that is the last thing. it could be and most likely is a vacuum leak on that bank at the upper intake.
other possibilities is the pcv, low fuel pressure or a mass air flow sensor.

Roy
Roy,you are good. fund a damage hose elbow type under my throttle body....thanks again for your help. Nathan6969 from Seattle wa. I wish you a good life.......