Okay, i can't really pin this down but its only started happening in the last few week possibly after it was dyno'd - the operator bounced of the limit a lot several times which resulted on my telling him to stop f@#king doing it!

As most people know i have a CTSC, also a lightweight traditional battery (that I've had a for a year), 1 step colder NGK iridium spark plugs, meth system, RC650cc injectors and Okada coil packs.

Always from cold, the car seems to subtly misfires/back fire on the okadas its quite subtle but you can feel it!, when its fully warmed up it doesn't do it!, then more often than not at around 7500rpm and 8300rpm WOT in say 3rd gear you can here subtle misfires/back fire, you can't feel it too much and again it doesnt happen 100% of the time.

I've changed okada coilpacks/spark plugs with no avail and checked wires/vac lines etc however changing back to standard coil packs it doesnt seem to do it from cold - i need to test this from cold as I have two sets of okada coilpacks.

I cleaned a shit load of sensors too, ground points. Could be injectors, though I'm sure the wideband gauge would show this.

Could it be valve clearances?, alternator/battery? though they were done say 15k ago.

Running out of ideas!