[stockli]

Hi guys, Im new here and new to jeepin. I just bought my first jeep and am having issues that I know you experienced guys can probly help with

Heres the story

Jeep was having hard time starting so: I replaced plugs, wires and battery cables. Also replaced the crank pos sensor.

After that jeep started right up and idled pretty rough but cleaned up ok. Car then backed out of driveway and as soon as I put in D, stalled.
Once stalled would not restart and I can smell the engine is flooded. Let jeep sit for a bit and bang starts up, idles, put in drive annnnnd stall.
Then its hard to start again.

Any advice or list of things to run over to get this issue straighted out?

A friend suggested the torque converter solenoid other than that Im thinking about cracking out the mm and checking sensors and replacing vacuum lines.

Thanks guys.

[GeologistFelix]

Maybe the Idle Air Control? It could be failing to give the engine enough air to maintain idle when you put it in gear. I'd think it would do the same when you put it in reverse, though. Just my two cents.

[stockli]

Anyone have a link to a how to on cleaning IAC?

Oh and it has a new battery in it too.

[tjwalker]

Your tuneup isn't complete without a new distributor cap and rotor. Inexpensive and easy to replace. Replace the fuel filter unless you have evidence that it has been replaced recently. Easy to do as it is located on the frame rail on yours.

I'd try cleaning the IAC and throttle body. Test AND adjust your throttle position sensor. The TPS on yours IS adjustable. Test fuel pressure at the schrader valve on the fuel rail. Should be 31 psi at idle.

Here's how to clean your IAC...

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The Idle Air Control (IAC) is mounted on the back of the throttle body. The valve controls the idle speed of the engine by controlling the amount of air flowing through the air control passage. It consists of a stepper motor that moves a pintle shaped plunger in and out of the air control passage. When the valve plunger is moved in, the air control passage flows more air which raises the idle speed. When the valve plunger is moved out, the air control passage flows less air which lowers the idle speed. Over time and miles, the IAC can get carboned up which can have an adverse affect on idle quality. Cleaning the IAC may restore proper function and is an easy procedure to perform and good preventive maintenance so it is never a bad idea.

CLEANING THE JEEP 4.0 IDLE AIR CONTROL

Remove the air filter cover, associated hoses and the rubber boot that goes from the air filter cover to the throttle body. Remove the IAC with a torx driver (2 bolts; one can be kind of hard to get to)


"Gently" wiggle out the IAC from the throttle body. Gasket on the IAC can be re-used if it is not damaged

Clean the IAC with a spray can of throttle body cleaner; inexpensive and available at any place that sells auto parts. Throttle body cleaner is recommended rather than carburetor cleaner as it is less harsh, safe for throttle body coatings and is best for this task. Use cleaner, a rag and a toothbrush and or Q-Tips. Be gentle; don’t twist or pull on the pintle that protrudes from the IAC as it is fragile and you could damage it.


Thoroughly spray clean and flush where the IAC seats in the throttle body with the same spray cleaner

It is also a good idea to clean the entire throttle body itself, the butterfly valve inside of the throttle body and all associated linkage as long as you have things disassembled

Reinstall IAC and check idle quality
　

[stockli]

thanks for the info.

I pulled the air box off and the throttle body was NASTY! Really really nasty.

Cleaned that up last night, but I wasnt sure about the IAC so I figured Id ask first.

Is it normal for the throttle body to be gummed up due to the hose from the valve cover? How often do you guys clean your throttle bodies?