I need to pick your brains for this one. I have a 2002 Renegade with a 3.7L with approx. 135k. One day it started running rough like it was missing real bad. While trying to accelerate, it started shuddering and hesitating with a severe lack of power. The Check Engine light came on. After stopping and checking that the engine was still there, I was able to start it back up and drive it home with no problems. I was able to read a P0304 "cylinder 4 misfire" code. Since then, I have replaced the #4 coil pack, all spark plugs (champion copper) crank position sensor, cam position sensor, IAC valve, the battery, and the #4 injector. I also replaced the fuel pump and filter, completely cleaned out the tank. It only runs rough when it is started cold. After the engine is warmed up and is allowed to be shut off, then when it is restarted it runs very smooth and with plenty of power. Any ideas would be greatly appreciated!