VH41 Coil Pack Problems

[Aussie VH41]

My VH41 has been developing a hesitation when the accelerator is depressed just off idle when at normal engine temperature. If the accelerator is depressed to about ¼ travel length the problem disappears.

I have been told that squirting WD-40 (or CRC, or RP7 spray for starting wet engines) into the hole where the spark fits on the coil pack will fix the problem. This does work for 4 or 5 weeks and my son with an SR-20 motor in a Silva had the same problem but the spray fixed his for the last 3 months and its still going strong.

Buying the 8 replacement coil packs is more expensive than buying a Japanese import motor in Australia but before I go down this path, is there anything else that may cause this problem? For example, the transistor packs failing etc.

I am guessing the spark load during is high when the accelerator is just off idle and there is a resistive path present.

The engine has only done 100,000 miles.