I have a 2001 4.0 XJ with all the same issues.After running awhile and shut it down.After restarting runs rough,acts like it has a revlimitter set at 2700rpm and cuts back when it downshifts.Have replaced Coilpack,Crankshaft and Camshaft positioning sensers.After driving awhile and shutting engine down when starting back up still have same problem.Also happens while sitting long times in rush hour traffic.CEL starts flashing and starts running rough.If I'm going 55-60mph can put it in Neutral,turn engine off,let coast a few seconds,start back up and it may run fine.Any answers?