Check Engine Light On problems of the 2002 Ford Mustang

I own a 2002 Ford Mustang gt with a 2-valve 4. 6l engine with only 46k miles. Around 1 Apr 10 I started hearing a distinct ticking noise from the engine. Not being that mechanically inclined, I assumed some lifters needed adjusting; so, I brushed the noise off. On 10 Apr 10 I was driving on the interstate when I heard a loud bang and then sounds that patted like a harley running out of gas. My check engine light flashed several times. Fortunately, I was only 2 miles from home; so, I sputtered the rest of the way. As I have a diagnostic tool, I checked the code and it read the #3 cylinder was miss firing. I called my mechanic and he told me to change the spark plugs. Once I figured out how to get all that done, I removed the coil from the cylinder and it was shredded with the coil dangling. I extracted the spark plug with no resistance because it was just sitting in the hole. To my surprise, it was the original spark plug that came with the car. I tried to put in a new spark plug, but it would not tightened at all. I attempted several times and even tried to make it cross-thread, but it would not take. When I took a good look at the spark plug, I saw where the bottom three threads were smashed flat and the metal that you gap was mashed against the electric diode. I called bob moore Ford in okc and the service writer, gerry, told me there were no recalls for that event. I asked him what could have caused it and he responded improperly torqued spark plugs. When I told him it was the factory plug, he said then hot rodding must have caused it. I told him its my wife's car and the car doesn't take any abuse. I asked how much bob moore charges to do a helicoil and he said $500. I let him go. I ended up taking it to a mechanic shop and getting the cylinder re-thread for whole lot less and whole lot better attitude. Hopefully, it holds.

The car dies unexpectedly. The check engine light comes on but the dealer says that they cannot find anything wrong with the car. This has happened on two different occasions, (while the car is idling and when the car is in gear moving). Ford said that this has been reported on numerous occasions but they cannot fix the problem because when the diagnostic check is done no problem codes are recorded. Have you heard of this problem occurring and what can I do to get the problem fixed.