A little over a year ago the coil pack failed. Engine was underpowered because it only running on 3 cylinders. I took it to a local garage who replaced it and it's been running fine.
Last week the engine warning light comes on, I had it booked in to the Ford dealership for a service anyway so asked them to look at it. They told me it was the coil pack. I thought this was odd as it was only done a year ago and the engine was running fine but they insisted that's what it was so I had them change it.
Today I was driving my car for the first time since they delivered it back and the light came on again after about 1 mile.
A series of unrelated issues while they had my car left me questioning their competency. So my question is, could they have gotten an old fault from the computer from when it actually failed last year if the other garage didn't reset it?
They are picking up the car again in the morning but I'm not paying for a replacement coil pack if the old one didn't need changing.