hi all i got a 2000 mk 2 1.2 8 valve punto when i start the car it judders and runs bad like a missfire, also when i put my hand over rear of exhaust the fumes arnt constant just like a misfire, so i put new spark plugs in, new leads, new coils still the same, put code reader on code p0351 primary coil pack A , but...... when i put a ignition tester between the spark plug and ht lead they are all flashing so none of them seem to be misfiring, the car runs like s**t and you cant pull off due to no power
any ideas this is an ongoing problem
im thinking new ecu but reading forums from what i can understand example 1 and 4 are not sparking but all mine seem to
please help.:bang:

Misfiring can be caused also by mechanical problem such as head gasket. Hope not but if you run out of ideas you could do a compression test. Also if you have multi point injection you could have a faulty injector. I would replace the ignition wires if they are old even if they appear like they working.

The ECU coil driver fault will affect 2&3 or 1&4. Pull plug leads one by one - the one which does not make the problem worse is the faulty cylinder.
If suspect plug is new, do a compression test. In fact do one anyway to rule out head gasket.
If its a coil pair of cylinders and coil is new its likely to be the ECU. Proof would be another coil that missfies on the same plugs.
If that is the problem ECUs can be repaired no need to replace at huge expense.

mine was miss firing and found out it was infact the sparkplugs