'98 Expedition 5.4 Code P0171

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khpony

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I've cleared this code twice. Both times it popped up was after fueling up. The book just says "System To Lean" but no further information. I have the '98 Ford shop manuals but apparently the OBD info is in a separate manual that's not included in the 4 voulme set I have. Is it possible the seal on the gas cap needs replaced or is it something else? Any help would be greatly appreciated.
 

97ExpGuy

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I've cleared this code twice. Both times it popped up was after fueling up. The book just says "System To Lean" but no further information. I have the '98 Ford shop manuals but apparently the OBD info is in a separate manual that's not included in the 4 voulme set I have. Is it possible the seal on the gas cap needs replaced or is it something else? Any help would be greatly appreciated.

This code for me was an O2 sensor. You need to find out which one though since there are four.
 

Lane24

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Try cleaning your MAF. Mine was the O2 sensor as well, and I cleaned the MAF, reset the codes and all was good. No more CEL. Check this link... there is a whole discussion about that code, and a little write up on cleaning your MAF and checking your vacuum assembly. It may help you. http://www.expeditionforum.com/showthread.php?t=4926
 
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khpony

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Lane24.....Thanks for the link. Looks like I'll be checking mine out the next several days.
 
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