Idle at 3000
12-10-2011, 11:18 AM
#1
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Year: 1989
Model: Cherokee
Engine: 4.0 Inline 6
Idle at 3000
Only happens after I get the jeep to running temp and turn it off. start it again, 3000 idle. turn off, then after a minute or 2 its fine again(sometimes takes a few tries)....any ideas?
12-10-2011, 11:28 AM
#3
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Year: 2001
Model: Cherokee
Engine: 4.0L
Try removing the idle air control and clean it with carb cleaner and re adjust the idle motor and reset it.
12-10-2011, 11:39 AM
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Year: 99
Model: Cherokee
Engine: 4.0
Haha, x3 on IAC valve. It is usually associated with high idle issues. Don't unplug it while jeep is running, it won't do mechanical damage, but it will throw off the cel with an inaccurate reading, making it more difficult to diagnose down the road. Also, with that said, go to a good shop with a code reader and see what it says. With the right diagnostic tool you can look at specific functions like how well/accurately the TPS and IAC are working..
12-10-2011, 11:40 AM
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make sure your coolant isn't low! that IAC valve has coolant running through it! low coolant flow in the IAC valve can cause the valve to raise idle higher than normal! seen this multiple times!
12-10-2011, 12:00 PM
#7
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Year: 99
Model: Cherokee
Engine: 4.0
Originally Posted by mossyoak20
make sure your coolant isn't low! that IAC valve has coolant running through it! low coolant flow in the IAC valve can cause the valve to raise idle higher than normal! seen this multiple times!
Last edited by VTJeep; 12-10-2011 at 12:04 PM.
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12-10-2011, 12:57 PM
#10
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Originally Posted by VTJeep
...really??... My 99s IAC valve sits on the TB, so having coolant in there means there is coolant in my TB, which means there is coolant in manifold and by proxy, the engine?? Also.. Why would idle AIR control valve have fluid in it? Either I'm lost and need to do some serious homework on my jeep, or there was a misstatement by someone...
12-10-2011, 01:11 PM
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Year: 1990
Model: Cherokee
Engine: The venerable 4.0
Its the throttle position sensor. There's actually a tsb on it. Try adjusting it down a .02-.04 volts on the engine side. Play with the adjustment you will find the sweet spot. Just don't go toooo far. It affects your shift points.
12-10-2011, 01:45 PM
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Year: 1990
Model: Cherokee
Engine: 4.0
Originally Posted by Slick761
Its the throttle position sensor. There's actually a tsb on it. Try adjusting it down a .02-.04 volts on the engine side. Play with the adjustment you will find the sweet spot. Just don't go toooo far. It affects your shift points.
