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Unread 10-24-2013, 08:36 AM   #1
Futuramic76
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Join Date: Sep 2013
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1999 Jeep Grand Cherokee, 375, 000 mi.

Great car, original owner, freq.oil changes.

Replaced my Crank sensor, alternator, MAP sensor. Engine is sputtering on warm start ups until I get on freeway. Gas mileage is down by 40%.
Fuel injectors?
Cam shaft sensor?
Spark plugs?
Vacuum leak?

Likely issue?

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Unread 11-01-2013, 07:11 PM   #2
uberxj92
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1992 XJ Cherokee 
 
Join Date: Oct 2012
Location: umatilla, florida
Posts: 1,961
Wow. That's a beast. Got to live it. That's a hefty fuel drop. When was the last tune up? With ethanol you get half life on tune ups nowadays.
Check engine light on?
Could be o2 sensor.
Which engine do you have?
That many miles you may want reward her with a rebuild.
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Unread 11-01-2013, 07:25 PM   #3
Futuramic76
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Just replaced M.A.P. sensor, O2 sensor, fuel injector cleaner.
Think maybe a vacuum leak?
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Unread 11-01-2013, 07:26 PM   #4
Futuramic76
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4.7 L all-wheel.
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Unread 11-02-2013, 03:42 AM   #5
uberxj92
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1992 XJ Cherokee 
 
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Location: umatilla, florida
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Sounds vacuum. That's a lot if mikes on that particular engine. I'm impressed. Keep her up
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Unread 11-02-2013, 05:17 AM   #6
Duh
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I wouldnt rule out a sticking injector. Stuck open it will give a stuttering appearance at times when there is too much fuel and not enough air-think about stoichiometry.
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Unread 11-03-2013, 04:01 PM   #7
Futuramic76
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Thank you guys. I will explore those solutions.
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