Another easy one this, in hindsight.....
The coil packs even when the insulation starts breaking down still produce enough spark power, just that it 'leaks' out to the nearest ground rather than sparking in the combustion chamber (path of least resistance), that being tha aluminimum coil-pack holders/rails.
I have jus made a new coil-pack rails from Delrin (purchased from ebay), It's a bit fiddly but I made 2x new rails with basic DIY tools. Delrin is stable a type of Nylon I think.
DO NOT add any tape or anything to the coil-packs, maybe just clean them in solvent or petrol.
To remove all easy routes to ground for the spark 'leaks' I used cable-ties to secure the coil-packs to the delrin rails, 4 for each coil, rather than metal screws.
This has 100% cured the car I was working on. Thats less than $20.00 for 100% fix.
Go ahead, try it, easy as that.
