codes 0171 & 0174 keep popping up on my 1998 Expedition 4x4...4.6 V8.....recently just went through the 0401 EGR phase and now this.....Please any info or suggestions will be apreciated........Thanks Jim

 

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For some reason my expy took a F85Z-6C324-CA visually inspected the old one and still decided to replace it.......Still the same codes......been through replacing all the Oxygen sensors......numerous vacuum hose replacements....fuel filter.... and now complete PVC system replacement.....can't shake these codes..did the old hose to the ear listening and checking for vacuum leaks....still searching for the solution.........

 

Clean the MAF sensor. It is inside the air filter housing where the wires go into it. Take the housing apart, the side with the wires in it is taken apart by popping the flat plastic panel out of the front. Pull the rubber grommet out from around the wires and unplug the sensor in there. Pull the unit out with the flat plastic part (seperating it from the cylinder portion). There will be two trox screws holding the sensor in. Remove them, pull the sensor out (being careful not to lose the o-ring in there) and spray the contacts down gently in carb cleaner. When they get dirty (and they all do) the sensor can not tell the computer the correct air flow into the motor. It always will read low. So it will put in less fuel and bam, there is your lean condition.

 

Problem was fixed through either the cleaning of my throttle body or the replacement of my MAS.......thanks for the suggestions....

 

TYGER!!! Thanks that did the trick for me... https://www.ford-trucks.com/lc/lc.ph....com%2Fford%2F

My Expedition was showing both 0171 & 0174 codes as well as idling rough. There was a small hole in the PVC line and the boot that was connected to the manifold ALLLLLLLLLL the way in the back was torn up.

There is another place to check (went through this a few months ago): The battery shield cover lets battery acid drip on the vacuum lines. I just cut the lines a little shorter and shoved them in to the rubber boots. It solved the problem that time.

Thanks for the help!