Help Me Brobeans! 1995 ZJ 4.0L Hard Start Rough Idle -
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Unread 05-09-2014, 01:01 AM   #1
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1995 ZJ 
Join Date: Jan 2014
Location: Muscoda, WI
Posts: 6
Help Me Brobeans! 1995 ZJ 4.0L Hard Start Rough Idle

I have a 1995 Jeep ZJ 4.0L with 203xxx miles. My problem is on the startup. When I start it after sitting for a while it will crank and the engine will fluctuate rpms and shake. Sometimes it will catch and fire up, sometimes I will have to try at it a few more times until it starts. It seems to fire up right away if it was just recently on.

When I finally do get it started it has a rough idle for sometimes up to a minute where it sounds like it has a cam and then it will kick out of it and idle fine. Ive done the key trick and haven't got a code.

I am at a loss as to what it is and any input would be deeply appreciated. Thanks!

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Unread 05-11-2014, 09:28 AM   #2
2004 TJ Wrangler 
Join Date: May 2008
Location: Lake in the Hills, illinois
Posts: 2,049
Before cranking the engine when cold, cycle the key on and off to cycle the fuel pump on and off. You will hear it run if you listen.It runs for a couple of seconds. do this 3-4 times. This fills the fuel lines with fuel. The small antiflow back valve in the fuel pump may have worn out. If it starts and runs good just get in the habit of doing this.

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