My 99 XJ 4.0L has developed an intermitant problem. Occasionaly it does not want to idle unless I keep my foot on the gas and keep it around 1000 RPM. If I take my foot off the gas it just idles right down to zero and stalls no rough idle or chugging it just stalls. So far this has happened once while the engine was warm and once while it was cold. Jeep has around 128,000 miles and is otherwise trouble free. No check engine light. Any ideas on where I should start looking?

 

I would say try your throttle positioning sensor, idle air control valve/sensor and then fuel filter