I had my boost raised last week and my car is now backfiring / cutting out for an instant when on peak boost. When I was having the boost raised there was a severe misfire due to the "spark being blown out", this appeared to have been cured by new plugs/leads/dizzy cap, but it appears not totally.

I have not had the boost raised significantly (it peaks at 13 PSI and then drops down to 10-12) so I cant see that special plugs should be needed. Therefore I wonder what else I should look at in terms of wiring etc. I have also read about something called a group A coil which increases spark intensity. Would one of these help me?. What other things could be wrong with the ignition system?.

Any advice would be welcomed, I want to try and fix this myself if I can.

Best Regards,

Stuart