I own a 2000 Ford Excursion with a V10. While driving home from my son's track meet in a construction zone on I94 in mount clemens Michigan during rush hour I had a spark plug blow out. We (my wife, my son and I) were moving about 10 miles an hour in the construction traffic when we began to slowly speed up. I accelerated and boom, there was a very loud sound of knocking. I nearly hit the dividing wall it scared me so bad. I was able to pull over about 150-200 feet ahead through the construction barrels. I opened my hood and discovered that one of my coil packs was sticking up a few inches and broken. I called my insurance company (usaa) for roadside assistance. Within an hour and a half they sent a tow truck and had me towed (about 7 miles) home. The next day I was able to better inspect what had gone wrong. The motorcraft spark plug had completely un-threaded itself and the compression of the motor turned the spark plug into a projectile that completely demolished the coil pack. The coil pack snapped from its retaining bolt and was beating against my fuel rail. Luckily I was able to pull over as soon as I did because I could only imagine if I had been in an area where I was traveling the actual 70 mph speed limit and the damage to my fuel rail could have been disastrous possibly causing a fire. I contacted russ milne Ford in clinton twp Michigan about this issue and they stated that it would cost over $1000 to replace the head and that it was caused by the threads on the head or improper torquing of the spark plug. I found that amazing since I had my truck serviced by them about a year before because of an slight engine knock that I had on the passenger side of the motor along with a few other minor things. They never were able to find the cause of the "engine knock". unfortunately for me the engine knock was a sign of the pending failure that I wish had been discovered before the blow out. No repairs yet.

- Chesterfield, MI, USA