I own a 2003 Expedition with the 4.6 engine. I continually have problems with the coil packs. I had been taking it to the dealership but I don't feel I am getting the satisfaction with their service. They had been telling me that the coils go bad due to dirt and the like fouling them. I have talked to several people and looked on the internet as to how to go about finally correcting the problem.

I discovered that they are not difficult at all to change out myself. I also decided to change out the spark plugs at the same time. I had been told that the spark plugs should be changed with the replaced coil. It looked like neither spark plug had been replaced. I also noticed that there was a lot of dirt and grit around and inside the boot of the coil pack.

I have 2 questions. First, is there any way that you can prevent the dirt and grit from getting inside the coil pack. If that is the cause of the packs going bad, replacing them is not really fixing the true problem. Second, how can you determine which coil pack has gone bad. The computer I had my vehicle hooked up to was not able to pinpoint that, it only identified an ignition problem.

Any help is appreciated.

 

With these packs you have to have the equip. to test one. One tester is a load tester. Puts the coil under load to see if it fails.
As for figuring which one is bad, they have a way at the dealer to pinpoint which one it is w/o a code. Took them 30 minutes or less and cost me 80$ for their effort.

 

I have a 2002 Ford Explyer. I had to replace two ignition coils last year, now two this year. I have 80K miles. Once they start going bad they all eventually have problems. My check iengine always comes on and I have it checked at Autozone. It's always a cylinder mis-firing, and is always a coil. Plugs are all new. Thinking about just replacing the last four coils that are original equipment.