Misfire under load only above 2000rpm

[Integrale1]

My 172 tonight developed a misfire randomly during my journey home. The symptoms are :

1) misfiring cylinder only above 2000rpm
2) does not misfire when you rev the car stationary
3) no dash lights illuminated
4)does not do it when it’s on the initial engine start cold fuel map

Doing some invest I’ve checked and cleaned all the plugs to the sensors, checked the spark plugs and disconnected sensors to see if they affect the fault. No joy

looking at the coil pack it was showing signs or burning so I have replaced that, fault still there.

My only other initial suspicion is a faulty ignition lead purely down to the damage on the old coil

Any ideas? Any advice/help would be greatly appreciated

pics of the old coil pack

 

[Robbie Corbett]

Got a multimeter? I had a s**t ht lead which did similar.

 

[Integrale1]

So, changed all the plugs, ignition leads and the coil this morning. Took it out for a drive, same problem but this time the eml illuminates on the dash.

Managed to get a code reader that identifies the misfire as cylinder 4 which led me to start suspecting the injector.

Started the car up, unplugged number 4 injector no change in the cars running. All other injectors made a noticeable difference to the running. Looked at the plug and noticed the insulation was damaged and both wires had bare copper touching.

Fixed the insulation, plugged the injector back in and faults fixed, bad wiring all along 🙄