Mitsubishi Repair: ignition coil problem, power transistor, cable harness

Question
I have 2000 eclipse RS, 5 speed and I have continues ignition coil problem. My engine is loosing its power during the acceleration and shifting. I am getting error cone misfire on Cylinder 4. I have swapped the coils and the problem was following the bad coil. (I got the error cod for different cylinder). So I have replaced the coil, but in few days the problem came back and the coil in same location got bad. First couple days after I have installed the coil the engine drives fine, but then I have the problem comes back and I have problem to determine what is causing to get the coil bad/// any help?

Answer
George,
This sounds like a cable harness that attaches to the ignition coil is faulty, or possibly the power transistor the harness attaches to.  It's also possible the spark plug itself in cylinder #4 has a crack on it and its arcing.  Enough arcing could cause the coil to overheat and eventually fail.  Since coils can be expensive, you may want to have the harness and related connections inspected to make sure those are working properly.  Replacing the spark plugs would also be a good idea, and be sure not to over-torque them when installing them.
Good luck!