Yesterday I was driving the Cherokee home from the grocery and when I started to pass a slower vehicle (unusal for me), The engine slowed some when I gave it more gas. I slowed to about 50 and it hesitated several more times. I started to fear I wouldn't make it back without incident and I didn't do anything to try to make it change. I just slowed a little more and kept heading home. I didn't want to get stuck with a bunch of food that needs to be kept cold. After I got home, and offloaded, I checked for trouble codes, nothing, Just to be sure I connected the scanner, no codes stored, all operating readings looked normal, the jeep seemed to run perfectly. I checked the key on fuel pressure and while running and all is normal. The day before, a couple of times when I started the Jeep the idle jumped up to about 2000 rpm and stayed there for about 15 seconds then it slowed to about 1000 and I got tired of waiting for it to slow down and took off. A couple of times while sitting at lights I noticed an occasional very brief stumble in idle speed. So I join the ranks of 4.0 owners with mysterious symptoms and not many clues (WooHoo!). I don't believe it's contaminated gas or fuel pump or filter problems, can't find any vacuum leaks, CPS is less than 3 months old. Any suggestions on where to look next? I'm fixin' to go for a ride to see if I can get it to do it again. <img src="/forums/images/graemlins/confused.gif" alt="" />