Some 2002-04 Jeep Grand Cherokees with 4.7-liter engines are prone to producing a rough idle when at a stop, with the transmission in gear and the engine at normal operating temperature.
Chrysler says if the check engine light is off when the rough idle occurs and there no trouble codes stored, the PCM is in need of updated software. Check with a dealer for the specifics of the flash.
"Factory Fixes" is written by Jim DePalma, a 30-year veteran of the auto repair business who has served stints as a service manager, parts manager and ASE-certified technician. His column provides vehicle manufacturers' authentic factory technical service bulletins (TSBs) that have been condensed for easier reading. Mr. DePalma advises that techs always check with a dealer or repair information system for the latest revisions before starting to work on a vehicle. He can be reached via e-mail at [email protected].