Warm Start Problems

I have a 2001 Cherokee Sport 4.3 L 6 cyl. It had 121,000 miles on it when I bought it and now has 145,000. The whole time I owned it, on warm starts it acts like it is flooded and chugs until it smoothes out and turns on the check engine light. Cold starts are no problem. The trouble codes indicate misfires in various cylinders. I have replaced the spark plugs, spark rail, all fuel injectors and cleaned the throttle plate all to no avail. I will clear the trouble codes drive a little while with no problem and then all of a sudden, on a warm start, chug, chug, chug and the engine light. Anybody have any thoughts as to the problem and how to solve it?

Doug, those 4.0L engines of that year are notorious for what is called heat soak. You shut it off and heat from the header comes up and vaporizes the fuel in the rail and will make it miss until all the vapor is ejected through the injectors. The only fix offered by Jeep is insulation for the rail. If I remember, there was a bulletin on this and recall. You might be able to get the kit free.

I'd like to know more about the the rail insulator. mine does the same thing on hot days

there's also a heat shield that goes between rail and exhaust. Doug, is yours still there?