Runs rough at low RPM's

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Nov 8, 2009 | 09:14 AM

chilixj99

Thread Starter

Seasoned Member

Joined: Aug 2008

Posts: 353

Likes: 0

Year: 1999

Model: Cherokee

Engine: 4.0

Runs rough at low RPM's

My 99 XJ starts and idles fine. When I leave the house and am driving slow through the neighborhood it runs very rough, like it is losing power. This just happens for a 1 or 2 min then it runs fine. I replaced the IAC valve but that didn't fix it. Could it be TPS or PCV? Thanks for the help

Nov 8, 2009 | 11:03 AM

That Jeep Guy XJMJ

CF Veteran

Joined: Jun 2009

Posts: 2,611

Likes: 447

From: Michigan

Year: 1987 MJ, 1973 J2000, 1986 XJ, 08 JK

Model: Comanche (MJ)

Engine: 4.0L H.O

try a basic tune-up spark plugs spark plug wires, distributor cap and rotor

Nov 8, 2009 | 01:42 PM

RenoXJ

Senior Member

Joined: Jul 2008

Posts: 803

Likes: 0

From: Reno, NV

Year: 98

Model: Cherokee

Engine: 4L

Mines been doing that spuratically. Im afraid its the CPS..

Nov 8, 2009 | 07:17 PM

chilixj99

Thread Starter

Seasoned Member

Joined: Aug 2008

Posts: 353

Likes: 0

Year: 1999

Model: Cherokee

Engine: 4.0

Jeep Guy, I did a tune up when I bought it. I replaced the MAP sensor and the TPS today. I guess I'll see if that fixed it when I leave for work in the morning. It's just wierd to me that it only happens when the engine is cold.

Nov 8, 2009 | 07:40 PM

kitsapfreerider

Seasoned Member

Joined: Apr 2009

Posts: 457

Likes: 1

From: Appleton Wisconsin

Year: 1997

Model: Cherokee

Engine: 4.0

Bad O2 sensor does this.

Nov 8, 2009 | 08:10 PM

dieselfreek

Junior Member

Joined: Oct 2009

Posts: 48

Likes: 0

Model: Cherokee

mine was runing like crap at low rpms and bogging down then taking off? i took throttle body off and cleaned all the carbon out of it and the sensors with carb/throttle body cleaner and now its fine?