91 yj 4.0 H.O. - Jeep Wrangler Forum

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Old 02-16-2013, 10:45 PM
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91 yj 4.0 H.O.

My wrangler started lopeing at low speed but idles smooth and runs like a scalded Dog at highway speed anyone have any ideas.
It has the 4.0 H .O. and 5 speed manual trans.
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Old 02-16-2013, 11:01 PM   #2
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Sounds like its running lean. Pull the plugs and number them. Look at each plug and check the color of the core carefully.

94 YJ Black/Tan 4.0L 5Spd
4" RC - .5" Boom's - 1" BL - 15x8 Pro Comps - 33x10.5 GRABBERS - TJ Fr. Axles - RR CAI - RC Stabilizer - Bunch of other goodies!
My build:
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Old 02-17-2013, 09:24 PM   #3
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Here is a plug chart to help out.
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89 2.5 TBI, 4" RC lift, 1" Booms, SYE, Adams Driveshafts front and rear, Ford 8.8 with 4:88s, BFG 33X12.50X15, and a ton of other stuff.

AF Jeep Club Tail Number 184
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