Have a 1998 Jeep Grand Cherokee with the 4.0. The jeep will not idle and there is no check engine light on. The jeep seems to be idling to low, if driven the jeep runs fine let your foot off the throttle and it will stall. Had to double peddle the jeep home to keep it running. Don’t know where to start.

 

For stalling, LOAD TEST your battery. It is a common cause of stalling. And yes, you can have a battery strong enough to start the engine, but marginal enough to give the engine management system fits.

Any parts store will do this for you for free.

Could be something else, but gotta rule the battery in or out early in the troubleshooting process.

 

I would change your Throttle position sensor and or Idle Air Control Valve. Your IAC you may be able to remove and clean with carb cleaner and a tooth brush but your TPS should just be replaced.

 

if you disconnected the battery for a long period of time, the computer can forget its idle, had this happen to mine, i just put a nut over the pop out thing on throttle to hold it up enough for it to idle well under the hood, drove it for a while, then took the nut off and it idles fine now

 

iac motor try cleaning it first