I noticed that my standard AFM's read differently with HKS filters, and I thought one was faulty.
So I upgraded to nismos because I was thinking for the future and they have the same difference (well slightly less because the relationship between airflow and voltage on the nismo's is different).
On boost the rear turbo AFM reads less than the front then on trailing throttle the difference reverses. I think it is down to the different shape and length of the path from filter to turbo inlet, which affects the flow distribution through the AFM housings.
Pete, I doubt it is the cause of your misfire as the PFC uses an average (sort of) of the two readings to calculate load. Have you tried cleaning the earthing points. Come to think of it my intermittent misfire has become less frequent since cleaning up a couple of the chassis earth points. As you have an R32 you could just run extra cable from the battery -ve terminal to the ignitor earth and a few extra to the chassis. This isn't easy on the R33 as the battery is in the flipping boot!
