2000 Honda Shadow 1100 misfire above 1500 RPM

Have a 2000 Honda Shadow 1100, all of a sudden it would not accelerate much over 1500 rpm, and would pop and backfire. Initially thought it might be fuel related, but issue came on to quickly. Check fuel volume per service manual and checks ok. Ran bike off of external fuel pump setup (automotive Motorvac machine) same result. Did pull carbs just to make sure no debris in bowls and jets are clear. Hooked up 4 channel lab scope and watched pulse generator signal, 9 peak sawtooth pattern which corresponds to the 9 teeth on the sensor reluctor wheel, and that pattern stays constant when condition occurs. Back probed front and rear coil power wires at ICU. At idle both show a similar and standard ignition coil wave form, but as you come up in the RPM the signal for the front cylinder coil flattens out and miss corresponds. Removed coils and ohm test primary sides, both read 2.8 -2.9 ohms warm. Swap coil positions and re-run scope patterns, patterns remain the same with the front coil pattern going flat as the RPMs increase. Believe that if it was a coil issue then pattern would have reversed. I am down to believing the issue is the coil driver in the ICU, but have been unable to find any information, or much of diagnostic testing of the ICU in the OE service manual or online. Wondering if anybody has had or run into the same issue, or knows where I can get good waveform patterns for comparison before I spend a lot of $$ on a used ICU as they are no longer available from Honda.