I've got a 91 Civic Hatch with a D15B non vtec w/Multi Port EFI swapped on it. I have a PM6 ECU running it all. The D15s got an SOHC ZC cam in it too.
On to my question, I have a fluctuating revlimiter. I know on the PM6 ECU the rev limiter kicks on at 7100 RPM. I had the exact same Multi Port manifold, wiring harness, and ECU on my old D16 and it ran just fine. Hitting the limiter at 7100 every time. I know that when the motor is cold that the rev limiter is dropped to 6800. The only difference in the EFI system is a different Distributor and a Nology external coil. I have an MSD pro cap on the dizzy as well. I put the new dizzy and coil on along with the EFI at the same time.

What could be the cause of this? Sometimes the rev limiter kicks on at 6700, other times at 6800. And once in a blue moon I can take it all the way to 7100. Temperature of the motor doesn't change anything. Air temp doesn't make a difference either as I've had the same problem in scorching 100+ heat and 60 degree nights.
Please help me!
My thought is possibly it is in the distributor or the nology coil, but I'm not sure as to why they could be causing it, but those are the only differences in the system from when it was on my D16 and worked fine.

I know I posted this in the EF Civic/CRX forum already, but no one in there knows anything... please someone help me out!

Thanks,
Davey