>         How's this for a theory: The new filter caused the AFM wiper to
> sit in a different position for your normal cruising speed compared to
> the old filter.

Tony,
I think you have the logic reversed...
it's the position of the AFM wiper that determines the fuel injection pulses
and thus the cruising speed; not the other way around...

even if the filter allows more (or less) air to flow through the AFM the ECU
should adjust the fuel injection pulses accordingly....

Bill