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Old 02-13-2011, 01:57 AM   #1
Join Date: Feb 2011
Posts: 3
help with jeep running lean at highway speeds

hi, im new to this form and have little know how when it comes to jeeps because im only 17 but have some help from my dad. im having trouble with my 1995 2.5l yj running lean. the check engine light only comes on when im driving 55+mph. the light never comes on when im just driving around town. a few months ago i somehow ripped the wires on my 02 sensor but got that replaced asap. i also put new spark plugs in and distributor cap. im just wondering what could make the light only come on at a higher speeds in 5th gear, and things that i could check to find the source of the problem.

thanks, yj kid

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Old 02-13-2011, 08:14 AM   #2
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Location: Hofterup, Sweden
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Time to change the fuelfilter?

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Old 02-13-2011, 09:55 AM   #3

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How does it run when you are at highway speed? Running lean will usually cause it to run hotter. If the O2 sensors are correct then you may be introducing "extra" air into the intake through a crack in the manifold or a bad gasket on the throttle body.
Nothing is foolproof to a sufficiently talented fool.
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Old 02-13-2011, 01:27 PM   #4
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Location: Las Cruces, NM
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What codes do you get??
(Sold)1994 Jeep Wrangler 2.5L, Bestop top
/w steel half door and slider windows
5 speed, 2.5" lift, 31" tires,rack lights
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Old 02-13-2011, 10:25 PM   #5
Join Date: Feb 2011
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im getting the code 51 which is the oxygen sensor signal input indicates lean air/fuel ratio. i have a fuel filter from a tune up kit that i got but have not put it on yet, i will see if that fixes it. when im driving on the highway i don't notice it getting any hotter but i dont spend much time on them. other than that it seems to run as good as any 2.5l yj at highway speeds no weird sound or anything
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yj running lean

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