Hi,
I have a 2003 Ford F-150 5.4 SOHC Triton V8, 78 000 Km.

I noticed a vibration caused by a cylinder misfiring and the "Service engine soon" light came on at the same time.
A mechanic changed a coil, telling me that it looked fine but maybe there was a cut in it or something, and that fixed it.

Two days later, the light came on again and that same vibration (although at times it's nearly unnoticeable, but the light stays on).
And after talking to the truck's last owner, I learned that he had the same problem and got them all changed!

Does anyone have an idea on what could cause multiple coil failures?
I read it could be the coil seal; water could be shorting the coil (and there’s snow here, that would make sense).
One thing is for sure, it's not the coil itself, it was new! (If it's the same, that is).

Any comments/personal experience will be greatly appreciated.

 

In the spring of last year I bought a 98 F150 w/ the 5.4 Titan. Couple of weeks later started having problem when I called for power such as going up a hill or hard accelerate to pass would start missing. Thought that it was possibly bad gas, so I added dry gas and then a fuel injection cleaner. Problem persisted.
Pulled the plugs and found that somebody had put a regular plug instead of a dbl platinum in #2 position. Not knowing why they would do such a stupid thing, I went ahead and replaced all eight plugs and new COPs in # 1 & 2 positions. Month ago devolped miss again and blinking check engine light. Ran scan and said bad COP in # 4 position. Installed new COPs in # 3 & 4 position. Was intending to replace all 8 anyways not knowing what their life cycle was. Anyways two weeks after installing these two, devolped miss again with blinking check engine light. Ran scan, #3 COP bad. Replaced and has been running fine since.
Problem is that in checking Wells site for specs, according to them # 3 & 4 was in spec for both primary and scondary. They have suggested that I look real close for signs of a greenish tint because it appears to be a common problem for number three and four to devolp problems because of coolant leak being they are located under the heater hoses and that over half that are returned are found to have the greenish tint to them.
They highly recommend that you do use the little packet of cream included on both the plug in cop connector and at the end that contacts the plug.
Still don't know if they in fact do have a life cycle, but time will tell.
Currently have installed 4 Well in position 1-4 and 4 OEM (Motorcraft) in 5-8.