Intermittent misfire - weak coil pack?.

[rustyroger]

My 2001 Zetec 1.25 fiesta has a misfire that comes and goes. When it is missing I hear crackling through the radio.

I have traced the culprit to #2 cylinder (2nd from cam belt side), I have replaced the plug leads, which made no difference, and swapped the spark plug with #1 which also had no effect. Lifting one lead at a time is how I made my diagnosis.

I have given it a compression check, all cylinders are showing about 180 psi, with less than 2% variation.

So I thought it must be a bad injector, quite simple to do, but that too has made no difference.

When I pulled the plug leads it seemed to me there was a more powerful spark on the the other cylinders. I still had a spark but perhaps not the lightning bolts from#s 1,3, and 4.

Is this just my imagination?. I'm guessing the coils are one per cylinder, rather one coil firing two cylinders. Before I throw money at this, does anyone have experience of similar issues?. Am I looking in the right direction?. Or is there something else I should check?.

The engine light has come on btw.

Roger.

[Bobr]

Fiestas around that era did have coil pack problems.   I had to limp to a ford Garage in 2006 and have a new coil pack fitted.

[rustyroger]

I replaced the coil pack today, so far all is well!. :)

 

Roger.