87 xj idle wayyy to high?

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Jun 18, 2010 | 11:00 AM

mikeg216

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Joined: Sep 2008

Posts: 126

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Model: Cherokee

87 xj idle wayyy to high?

so i did a tune up and adjusted the idle down but now its over 2k and my exhaust manifold is running red hot, i have no ideas as to whats going on can anybody point me in the right direction

Jun 18, 2010 | 11:02 AM

superj

CF Veteran

Joined: Feb 2010

Posts: 2,004

Likes: 40

From: corpus christi, texas

Year: 1999

Model: Cherokee (XJ)

Engine: 4.0 I6

vacuum leak. the red exhaust is from a lean mixture and the idle being up is from the air causing the lean mixture

Jun 18, 2010 | 11:06 AM

RENIXBEAST

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Joined: Aug 2009

Posts: 958

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From: Effingham, N.H.

Year: 1989

Model: Cherokee

Engine: 4.0 I6

My first guess would be the I.A.C. located on the throttle body. Probly NFG, unplug it and see if anything changes.

Jun 18, 2010 | 11:15 AM

mikeg216

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Joined: Sep 2008

Posts: 126

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Model: Cherokee

thanks guys gonna go check it out

Jun 18, 2010 | 01:03 PM

alpine.adrenaline

CF Veteran

Joined: Aug 2009

Posts: 1,127

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From: 9000 ft, CO

Year: 1999 XJ

Model: Cherokee

Engine: I6 4.0L

Quote:

Originally Posted by superj

vacuum leak. the red exhaust is from a lean mixture and the idle being up is from the air causing the lean mixture

X2, you have air entering somewhere, probably between your intake manifold and cylinder head. Use an unlit propane torch to find it, your engine will run different when it sucks in the propane.