Hi Don;
I don't have one of Tracy's EC-2's or a Renesis CAS so take this with a grain of salt.

A noisy CAS signal / bad ground is the bane of 2nd gen CAS with RX7's.
A search for a 3800rpm hesitation on the RX7 will yield a lot of hits.  It is grounding related.
Are the CAS wires shielded?
Is the shielded wire grounded to the EC-2 end only?
Is the EC-2 grounded to the engine or battery?
I am not sure what Tracy is using for signal conditioners- a small capacitor across the
CAS G+/- wires has helped on the Megasquirt.
Have you scoped the signal?

You won't want to hear this either, but, most fuel pumps are only good for a small number of air sucking/overheat events.
Also applies if you uncover the inlet doing hard sideslips on empty tanks or whatever.  Your current pumps are one step closer to dying.

Cheers
Cary