Misfiring problem comes back like boomerang. I have put NGK BCPR7ES (3330) and still have misfiring!
I used to drive using NGK BKR6EP-11. After making my car BPU I have noticed misfiring (not only at high boost of 20 psi but also at 0 boost at high rpm). After some discussion on the forum, I have decided to check coils connections and to change spark plugs to 3330. I have done it yesterday and made some tests. Car is powerful but sometimes especially at high rpm (5000-6000) it is misfiring. Strange think I have noticed is that: on full boost it is accelerating pretty well, but while driving after that at high rpm about 5000-6000 with no boost it is misfiring.
Coils looks OK, but never been changed – you can not see any signs of high Voltage on them (misfiring) rubber parts looks fresh, connections are perfect. I am stupid – I do not know what to do. I do not want to spend fortune on new 6 coils because I would prefer to spend it for new modifications.
Please help

I used to drive using NGK BKR6EP-11. After making my car BPU I have noticed misfiring (not only at high boost of 20 psi but also at 0 boost at high rpm). After some discussion on the forum, I have decided to check coils connections and to change spark plugs to 3330. I have done it yesterday and made some tests. Car is powerful but sometimes especially at high rpm (5000-6000) it is misfiring. Strange think I have noticed is that: on full boost it is accelerating pretty well, but while driving after that at high rpm about 5000-6000 with no boost it is misfiring.
Coils looks OK, but never been changed – you can not see any signs of high Voltage on them (misfiring) rubber parts looks fresh, connections are perfect. I am stupid – I do not know what to do. I do not want to spend fortune on new 6 coils because I would prefer to spend it for new modifications.
Please help