Jeep will not start/run -
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Unread 08-26-2011, 06:49 PM   #1
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1991 YJ Wrangler 
Join Date: Jan 2007
Location: El Jebel, CO
Posts: 681
Jeep will not start/run

The Jeep was running fine then the other day I jump in it and it fires up then rpms drop steadily until it dies. Now when it does fire the rpms go up to about 1000 then it drops and shuts off. I have replaced the MAP and TPS sensor and nothing has changed. At one point I tried starting the Jeep without the MAP sensor plugged in the Jeep would start but idle very rough, if I hit the accelerator it would die. One time while just letting it idle rough all of a sudden it went up to about 2000rpm and dropped jump up again then dropped until it dies. for the most part I cannot even get it to start now. At times with the ignition turned it is firing and trying to start but as soon as you let go of the ignition it dies. I am at a loss to what is going on and how to fix it.

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Unread 08-26-2011, 06:55 PM   #2
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1994 YJ Wrangler 
Join Date: Oct 2002
Location: Sevierville, TN
Posts: 1,118
I know this generic but have you ruled out the simple stuff like the dist. cap and rotor and maybe even the coil and the coil plug? also are you getting a CEL? if so have you checked to see what code it is throwing?
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Unread 08-26-2011, 07:51 PM   #3
Web Wheeler
1991 YJ Wrangler 
Join Date: Dec 2010
Location: 14304 Niagara Falls, NY
Posts: 2,537
Whats your fuel pressure look like? Should be about 31 PSI.

Only other things that come to mind would be the IAC valve and the cam position sensor - since the cam sensor tells it when to fire, it can mess with the timing. And you know how changing the timing can change the RPM's.
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