I have an 02 Liberty Limited with 67,000 miles. I have recently noticed that when I stop at a light or stop sign the RPM's dip to about 500. The Jeep seems to feel like it is going to stall. This lasts for a few seconds, maybe about 30, then the RPM's are back up to 6 or 700.

Today, I pulled into a parking spot at work, but had to correct my position. When I put the Jeep in reverse, it stalled. Of course, it started right up again. It only stalled after the RPM dipped (like it always does).

I am wondering if this is simply the spark plugs, or what it could be. Any help here would be appreciated. Thanks.

I had that same thing happen with my '95 Dodge Avenger....i changed the EGR valve, spark plugs, had the fuel lines and pump replaced, and it still happened to me...whenever having to stop at a red light i'd have to drop it in neutral and give a little push on the accelerator to help keep it from stalling....never found out what was really causing it though and then the engine locked up on me one day. So I guess check your pulley's and belts make sure they are at the proper tension as well, that wouldn't hurt i suppose. Good luck getting it diagnosed, everywhere i took my Dodge they just said it might be an EGR valve but it was brand new by the time they started saying that.....

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Had 2005 KJ Rocky Mnt. Edition (destroyed)
Had 2006 KJ Sport 4x4
Have 2007 JK 4-dr Sahara 4x4 (tow package so stock 4.10s!!)
AEV 3.5" RS Lift; Schrockworks FR bumper and Warn 9.5ti winch; Cobra 75 CB; Rigid 50" LED light bar; Adventure Trailers (AT Overland) JK Kitchen setup in the cargo area.
Southern L.O.S.T. # 236487

Check for vacuum leaks at hoses and intake manifold.

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Early '02 Limited, Steel Blue, White Guts

When is the last time you changed your plugs? If it is more than 30k I would definatly change the plugs.

Other things to try: Get a can of fuel injector cleaner, I use Chervron with Techron.. Good stuff! Will cost you about $7.50 for a can that treats 20 gal.

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Rock On

Newman from CT
04 Liberty 3.7L 67k Miles Front\Rear Tow Hooks OEM Skid Plates Hella 500's Cobra 75 CB with 4' Firestick BFG 245/70/R16
Rock Rails by Ratmloud
Frankenlift
Al's Upper A-Arms
L.O.S.T. KJ Northeast# 023050
My First 4x4 Jeep Vehicle

I have an 02 and had very similar problems that got worse over time. A friend recommended I pull and check the idle air control. It was dirty so I cleaned it up with some contact cleaner and the symptoms immediately went away. A couple of weeks later thay started back up so I put a new one in and haven't had any problems since. That's probably been six months ago.

This same thing happened with my 5.0 L powered Volvo wagon (Mustang 5.0 in a 240 wagon, what a sleeper!) and it happens to my KJ. The thottle body and thottle position sensor would get dirty. Take the beather tube off the thottle body and take the position sensor off the side of the body and clean both the body and sensor well with acceptable cleaner. Be VERY careful. Some of the cleaners will not compress, and you may bend a valve. I did this on my old 76 Jeep Wagon and I bent a push rod.

Try this first, it should help.

Al

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One Ruby, One Grand Cherokee, One YJ, One disassembled CJ, one Chevy Mason dump, one hotrod IH Pick-up, couple of antique tractors.
Former owner of a 5.5 inch lifted KJ

Pump some seafoam through it, thatll fix it right up!

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LOST KJ'S
Where are you going???
Current Jeep: 2004 Jeep Liberty
-Atlantic Blue
-Air Ride Rear Suspension ; OME/Rustys Lift ; Powertrax Locker ; Moog Lower Ball-Joints ; 245/70/16 Yokohama Geolander A/T-S's on MOABS ; Flowmaster 50 SUV
Lost #007082
http://www.cardomain.com/id/jeepjeepster

Update:

Took Jeep (finally) to dealer who I purchased it from, still under warranty. They did 3 things

1. New spark plugs
2. Cleaned out throttle body - it was "very dirty"
3. Replaced a gasket somewhere between the transfer case and transmission because there was a leak.

I was there for 7 hours, as I live 1 hour from the dealer now. Drove the Libby home, and it runs like a champ.

FYI, my old Jeep (96 XJ) was in a 9 hour traffic jam on 75 in Kentucky. It didn't overheat, or anything. Ran great. Got into 2 accidents, both at low speeds, one hit the trailer hitch, one my brother hit someone with the tow hooks. The XJ has 140,000+ miles and runs like a champ. He drove from Detroit to Lexington (17 hour total). Lexington to Louisivlle, Louisville to Detroit with not one issue (besides 9 hour traffic jam, and 2 minor accidents). I miss the old XJ.