miss fire on 03 2.3 Petrol Galaxy

[morganandarchie]

Just wondered what could cause an intermitent missfire on a 03 2.3 petrol Galaxy
it threw out a plug last week which was refitted, this then needed a new helicoil to fit new plugs. The car seemed ok for the first couple of days but then started to missfire. Its not all the time as its ok for about 10miles then starts, we have taken it to our local garage and they can find anything wrong with it.

I did think it could be the HT leads or one of the coils going down.

Just wondered if anyone can shed some light on it

Many thanks

[insanitybeard]

Does your engine have the setup with one coil pack bolted onto the end of the cylinder head with 4 individual spark plug leads or does it have two separate coil packs which are hidden under the bolt down plate on the rocker cover which says something like 'Ford 2.3 DOHC'? Either way, the coil packs are prone to breaking down and failing after extended milages so that would be my prime suspect and starting point.