Engines running rough on start ups

Mumblewood

Mumblewood

TJ Enthusiast
Joined
Oct 9, 2019
Messages
918
Location
Renton Wa
So when I drive my jeep around it runs totally fine, but when it’s warm and shut it off for just a couple minutes it’ll run real ruff for about a min. Then clears up and runs great again.
A couple friends thought it was probably a leaking fuel injector but I just checked them and there all between 12.1-12.5 ohms (checked when engine was cold if that matters)
Little back story on the jeep. I’ve had it since new. 48k on the odometer regular maintenance. Complete stock except for a k&n drop in filter (stock air box) that I’ve had in it for 15 years. I keep it clean and don’t oil it.
Any thoughts? What should I check next?
 
The leaking your friends are referring to is caused by the heat coming up from the exhaust manifold. This will cause fuel to percolate out of the fuel injector causing a rough run for a few minutes; which usually occurs on cylinder No.3.
Does your Jeep have the factory heat shield between the intake manifold runners ?
I believe there was a TSB concerning this problem.
My '01 had a similar problem, but my engine has 150K.
The cure for mine was to replace the fuel injectors due to age and mileage.
 
If i am not mistake this is a common heat soak issue where the fuel vaporizes in the fuel rail,some fixes are: replacing the heat shield over the intake manifold, hood louver, or covering the fuel rail in a insulated cover. I remember seeing this in a thread somewhere else, I know that @Jerry Bransford knows the common fix.
 
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Update:

I got some heat soak things today, not the ones Jerry had posted, but some set of 6 my cousin said to check out ( he’s a mechanic and they were cheap so if they don’t work, oh well) but I drive around a bit today and had no issues so great!
Thanks for the heads up!!
 
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