Sudden coil failure after service

[NO2]

My 2004 Focus was in for an A service and no faults or problems were found. However on leaving the car had a miss come in under load.

When the car was returned to the Ford dealer we were told that the coil had failed and need to be replaced. $400 later the car is good with a coil and spark plugs replaced.

Considering that the car did not have this problem prior to the service I am wondering what actions would cause a coil to fail like that. Running the car with a lead off a spark plug and not earthed perhaps. But I am not an auto electrician to know the answer.

Ford are adamant that a coil can go at any time but I have trouble accepting that it was purely coincidence happening after they had been under the bonnet.

[ratter]

Without checking a service schedule, I think there is no tuning or coild removal as part of an A service, it is only a minor service.

[fordmondeoman]

either bad luck or more than likely they washed the engine bay down which possibly got water into the coil or around the leads may have put more load on the coil and then it pact it in hard to say though why it failed

[NO2]

They did wash the car. I haven't been around to check if they washed the engine bay. But that's a possibility

[Talldude]

I actually just changed my coil(after market part with after market leads) on my 03 LR focus and I have noticed that it starts better and it also idles better then before. Did have a few times when it took a couple of turns of the ignition to start the car.

So I am guessing these coils don't last long I'm afraid.

[WILDB]

A Service is only a minor service.

Unfortunately these things can just fail. I'd say it's an unfortunate conincidence that it happened directly after a service.

[player110]

Could this cause a pinging noise.(Failed coil)