I had the exact same problem, Mark.  For me, it was the rear rotor being flooded.  The air pattern inside the plenum ain't at all obvious, and it is extremely dynamic.  The fuel was getting bounced out of the intake runner of the front rotor, then blown to the rear.  

My fix was to cut a slot the length of the plenum, and slid an aluminum plate in.  This made it so that the runners don't see the air feed directly.  The air no longer blows past the front rotor's inlet on the way to the rear.

Mark Steitle <msteitle@gmail.com> wrote:

>I'm in a bit of a dilemma and thought I would put this out here for the
>group to ponder.
>
>First, this is a p-ported 3-rotor, running RWS EC-2 and psru.  I'm running
>460cc Mazda primary injectors and 60lb Deka IV secondary injectors.
> Primary injectors share a common fuel rail and are positioned close to the
>engine, between throttle plate and rotor face.  Secondary injectors are
>located ahead of the throttle plates.  As this is a p-port engine, it has
>three 1-bbl TB's, located very close to the engine.  Engine will idle down
>to 800 - 900 rpm, but I normally idle it around 1500 - 1600 rpm.
>
>The problem is this, the #1 rotor cuts out at low to mid-range RPM,
>evidenced by obvious reduced power, very low EGT's on rotor #1, change in
>exhaust tone, a dark residue in the #1 exhaust port and dark spark plugs on
>#1.  Just today I was able to get it to run normally with balanced EGT's by
>adjusting Mode 4, but I had to go *full CCW* with the program knob to
>achieve this.  (Mode 4 & 5 adjust similar to Mode 1)  Now it runs well
>mid-range and the dropped #1 rotor is happily firing away.  I still have
>some tuning to do, but after adjusting Mode 4, I can now move forward with
>that.
>
>To date I have tried the following:
>  1.  Performed a compression check - OK
>  2.  Swapped primary injector with #3 - no change
>  3.  Swapped coils with #3 - no change
>  4.  Replaced spark plugs - no change, except initially it ran better
>until the plug fouled
>  5.  Checked plug wires with ohm meter - checked good
>  6.  Sent EC-2 to Tracy for latest s/w and checkout - no abnormalities
>found, latest s/w installed
>  7.  Checked secondary injectors for leakage - none seen
>
>Can anyone suggest a reason why the #1 primary injector runs extremely rich
>when set to the factory default setting?  Is this something to be concerned
>with?
>
>Thanks,
>Mark