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International Automotive Technicians Network
Re: 97, 98, 99 FORD EXPLORER 4.0 DTC'S PO171 AND PO174.
Posted to Technical Discussion Forum on 12/28/2003

Hi John,

My "thumb rule" on these is to check the freeze frames. If it set at 0 MPH, idle RPM and partially warmed up, be VERY suspicious of the intake o-rings. If it set during cruise conditions, check the BARO value to see if you've got a skewed MAF. If BA... Login to read more.