Hi Guys, this is my first post, my Mondeo is only firing on spark plugs 1 and 4, 2 and 3 are not firing, I originally changed all spark plugs but this made no difference, next I tried changing the coil, again no luck, next I checked the cabling going into the coil and all the way back to ECU, it's functioning fine, finally I brought it to two different non-ford mechanics and got them to do a diagnostic test on it, both tests indicated a fault with the coil, now I already changed the coil for a brand new one, I'm thinking at this point that the ECU may be at fault, I'm thinking that the ECU is failing to send any signal for plugs 2 and 3 and is somehow interpreting this as being a problem with the coil. Any ideas or suggestions would be great.

If you swap the coil packs around, does the fault move with the coil pack, or not?

Hi, yes I tried swapping the leads around to make 2 and 3 fire, and they did indeed fire, so this must rule out the coil as the fault.

I'll be watching this thread, my mk2 2.0 has a very weak spark on the no3 cylinder & I've changed the coil pack and still the same problem.

Previous owner put new plugs and leads in it as well.

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if the spark follows the plug then its probably leads. If you change the leads / coils over from 1 and 4 to 2 and 3, does the fault follow? if so then change just one (the coil rather than the lead) and see if the fault follows the coil or the lead.

This is how you will determine which is at fault, its a process of eliminiation.

Hello, this issue has since been solved, turns out the problem was a faulty module within the ECU which is responsible for sending a signal to 2 spark plugs, bought another ECU and had a mechanic who's also adept with electronics swap a good module from the purchased ECU to the current ECU, result was the problem fixed and no need for programming or coding keys as only a module was changed.

What was the total cost in the end?