Okay, I have a weird problem. My 2004 WJ will start immediately when cold. If I drive awhile and then stop, it will crank but not start. If I let it crank for a few seconds, turn the key back to off, turn it to "on" briefly and then try to start, it fires right up. I have replaced the fuel pump, fuel filter and, for unrelated reasons, I completely rebuilt the engine, including replacement of starter, crank position sensor and fuel injectors. (As well as the usual stuff in a rebuild) 4.0 l engine, 275k miles on the car. Any ideas?