I was wondering if anyone has had a similar issue on the Zetec engine 1.25?

We have two Fiestas both the same year and engine 1.25 Zetec. One has a misfire and the engine warning light is continuously on. p-codes 351 and 352 are triggered. This suggests a low tension issue with the coil pack or wiring, possibly PCM. I checked what the signal to the coil pack should look like using the fiesta that doesn't have the misfire using a scope. I performed the same test on the faulty fiesta and the signal looked the same (on both coils in the pack) so I assume this rules out the PCM? I then swapped the complete HT system coil pack, plugs and leads between fiestas, the problem remained with the car not the parts. Any advice would be greatly appreciated going to do a compression test tomorrow, strange that the p-codes suggest a problem with the low tension side but the raw signal is same using the scope on both cars.

Does anyone know how the 351 and 352 p-codes are triggered in the PCM, does it compare the commanded current to coils with the actual as this might help me diagnose why the p-code is triggered.

Thanks.