I have a 2001 Wrangler 4.0 that despite my replacing many parts, is still running very rough. So a few hundred miles after I had the transmission rebuilt and the torque converter and crank sensor replaced, I developed a problem. The check engine light started flashing, the engine made a horrible rumbling sound and I lost half of my horsepower. I took it to the shop and they said the new crank sensor was faulty and replaced it. A hundred or so miles later and it did it again, took to a different shop and they couldn't find anything wrong and said it runs great. Another hundred miles later and the problem changed and is my current problem. I have no check engine lights on but it seems like the motor is not running on all cylinders. It runs horrible in idle, I have about half of the horsepower, and everytime I slow down to a stop it either stalls or almost stalls, I can stop it by putting it in neutral. I've read some of the forums and I have replaced the spark plugs, the ignition coil and the throttle position sensor. After I replaced the plugs it did run perfect for about a day, then back to the same. Now I dont know what else to try, please any suggestions are appreciated.