BogsEight

I have been driving my 06 RX8 now for 2 months. I had posted early here re MIAC which was following the normal pattern of presenting itself at 5-6,000 rpms while shifting. The hot summer days of late clearly had an impact on this situation as well.
I live in southern Ontario, Canada and it was a hot summer this year.

So I had a trusted Mazda dealer run a diagnostic. She has 89,000 km and she was stalling now and again while the ac was on during very hot conditions.
The results:
My ignition wires were arching and the fuel flutter valve was seriously carboned up.
2 grand later with a whole new ignition system and flutter valve my 8 is running like a champ.
Clearly more power, better idling and most importantly no MIAC. I ran it extensively as before and it seemed to clear up the problem.
However it has come back on a very limited basis within the last week or so, that is after she gets hot and during a shift change over 6,000 I do get some MIAC. No where near as bad but it still does occur now and again.

Any thoughts on this because it just doesn't make any sense. The problem MIAC seems to be about 90% better but not gone completely.