Engine idle rough 94 4.0 - JeepForum.com
 
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post #1 of 8 Old 12-26-2012, 06:20 PM Thread Starter
jeepbob94
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Engine idle rough 94 4.0

I have a 94 cherokee. I seem to have an issue with the engine not wanting to start, or if it starts runs great for a few minutes then starts to chug or sounds like it is miss firing. I have changed out the following parts already: Fuel filter, plug wires, dist cap and button, coil, checked and replaced some vac lines, added fuel stab if water was in fuel. I have fire, fuel, and air just not sure what it could be. any thoughts.

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post #2 of 8 Old 12-26-2012, 07:53 PM
jason280
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Clean your throttle body, and check your Idle Air Controller (IAC) and throttle position sensor (TPS). I had very similar symptoms with a '94 YJ 4.0, and it turned out to be the IAC. You can get them on eBay for fairly cheap...
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post #3 of 8 Old 12-27-2012, 04:52 AM
cruiser54
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Make sure all your intake manifold bolts are snug and present.

If you own a Renix Jeep, you'll want to check this out.

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post #4 of 8 Old 12-28-2012, 09:53 AM Thread Starter
jeepbob94
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So I have an update and yet no solution that has worked. Changed out Can Shaft position sensor, checked fuel pump, reset comp, changed coil, plug wires, dis cap and button, cleaned throttle body, cleaned Idle Air Control, checked fuel lines for obstructions all clear. checked vac system. what else could it be not it will not start,it will crank but not fire. last night when it was running I noticed when the secondary electric fan came on, the engine started to chug again and died. need help please! out of ideas, out of a job, and out of money.
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post #5 of 8 Old 12-28-2012, 03:12 PM
cruiser54
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Quote:
Originally Posted by jeepbob94 View Post
So I have an update and yet no solution that has worked. Changed out Can Shaft position sensor, checked fuel pump, reset comp, changed coil, plug wires, dis cap and button, cleaned throttle body, cleaned Idle Air Control, checked fuel lines for obstructions all clear. checked vac system. what else could it be not it will not start,it will crank but not fire. last night when it was running I noticed when the secondary electric fan came on, the engine started to chug again and died. need help please! out of ideas, out of a job, and out of money.
Bad battery, alternator, battery connections, grounds?

If you own a Renix Jeep, you'll want to check this out.

An index to over 30 write-ups can be found in the link below

www.cruiser54.com

My Jeep Technical Photos

http://www.cherokeeforum.com/g/album/1725214
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post #6 of 8 Old 12-28-2012, 11:46 PM
ratfink41
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Might have a cracked head or intake Mani crack, will suck in unsensored air, confuse the motor and cause it to stall
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post #7 of 8 Old 12-29-2012, 04:15 AM
cruiser54
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Quote:
Originally Posted by ratfink41 View Post
Might have a cracked head or intake Mani crack, will suck in unsensored air, confuse the motor and cause it to stall
Explain how the head could be cracked causing this.

If you own a Renix Jeep, you'll want to check this out.

An index to over 30 write-ups can be found in the link below

www.cruiser54.com

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post #8 of 8 Old 01-02-2013, 12:38 AM
seattle_yj
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I had the same issue the other week. It wound up being a bad fuel pressure regulator. Pull the vac line at the front of the fuel rail that connects to the regulator, if it's dripping fuel its bad. My was dripping fuel just slightly and it was enough to cause pretty bad misfires and would die. Have you check fuel pressure with a gauge? If it drops under 40psi ish it will cause the engine to stutter and be hard to start. Good luck.
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