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?