In March I bought a 2005 Focus Ghia 1.6 from a car dealer. Luckily I also bought an extended warranty that means I pay nothing for the first year in terms of repairs.

My engine management light came on in July. I took it in and the coil pack had gone, which they replaced with a non Ford part.

5 weeks ago the light came back on and the car was hesitating on acceleration. They checked it over and replaced the cool pack again with a Ford part. They also replaced the leads and plugs.

A week ago the light came back on and the car started hesitating again. It's booked in for Monday and I have no doubt the coil pack will have gone again. My question is, what could be the underlying cause of it to fail 3 times in 4 months?

Many thanks.

are they putting contact grease in the ends of ht leads?

also the connector/wiring to the coil packs are known to give issues

If the plug gaps are too wide this will result in a higher voltage which can cause the coil pack and/or leads to break down. The gaps may be set at 1.3mm out of the box. This should be reduced to 1.0mm.