Rough Idle then dies.

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Rough Idle then dies.

Unread postby AZ53WILLYS » Tue Apr 28, 2009 9:12 am

Hey guys maybe you can help me with a problem im having. My brother bought a 1988 Jeep Cherokee he bought it for 300 bucks so it needed some work after finding a similar jeep that was being parted out he got a new wiring harness and then got the motor to start up and run without burning up any wires or shorting out well now we cant figure out why it idles high sometimes and then real low and then it just dies i think its the TPS but i was also thinking it could be the fuel rail not getting the right amount of pressure. He changed out the gas tank put a new filter and pump on so i think that is all good to go but it just keeps idling rough then high then sometimes it falls down to where it almost dies.. so if anyone might have an idea of what it could be whether it really is the TPS or some other problem let me know! Thanks and keep tearing up the trails my friends!

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Unread postby scrambler 82 » Tue Apr 28, 2009 9:27 am

I would have to agree with your thinking, TPS is a possible answer and then I've heard of a CPS-crank position sensor also failing. Might try one at a time-neither of which is expensive!
D60 rear, 60 front 3 linked, spools, 5.38's and 39.5 IROK's, auto and a little 6 banger!
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Unread postby 4x4ndad » Sat May 09, 2009 7:10 pm

Check out the hose that runs to the map sensor on the firewall. if its disconnected or kinked those problems will occur. Also theres a hose at the intake manifold on the under side about the middle with high mileage they like to crack especially if motor mounts are bad. Lets in lots of unmetered air and the computor goes nuts trying to correct it. Just for giggles take some brake cleaner, or induction cleaner and spray arround intake area cheking for air /vacume leaks. if you hit any area and the idle changes youve found something.
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Unread postby blackd-out-chev » Sun May 10, 2009 7:50 am

crank pos sensor! mine was doin SAME thing...and that was the prob
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