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Unread 10-30-2013, 01:08 PM   #1
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Join Date: Oct 2013
Posts: 1
terrible gas mileage & code p0171

I have a 1999 Jeep grand Cherokee Laredo 4wd ... its throwing a check engine light so I went and had it read. The code is p0171 system too lean.. its says a lean air/fuel mixture has been indicated by an abnormally rich correction factor, right rear fuel system lean. The catch is my gas mileage is 4.6mpg (no joke) I have no clue where too start or what exactly is wrong.. can anyone help please & thank u

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Unread 10-30-2013, 10:54 PM   #2
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1988 YJ Wrangler 
Join Date: Aug 2010
Location: Chesapeake VA, Chesapeake VA
Posts: 512
Are there any other indications on the dash that are weird? Is the CEL and MPG the only indications you have? Does it lack power? Does it sputter when you get into the throttle? Does the thermometer indicate? Need more info.
'88 YJ with SOA and SYE and a bunch of custom crap from BWF in Chesapeake.
'97 XJ on 8" lift, double triangulated rear, long arm 3 link front, Eaton/60 with 5.14 gears.
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Unread 10-31-2013, 08:21 AM   #3
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2002 KJ Liberty 
Join Date: Dec 2009
Location: Colorado
Posts: 8,195
1st what engine,4.0 or 4.7?

Most common cause of that P0171(and/or P0174) is vacuum leaks.
'02 Liberty sitting on 35" tires,HP44,RockJock60,and AtlasII t-case
tjkj2002 is offline   Reply With Quote Quick reply to this message

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