Fluctuating neg. to ground on ignition coil

Righto. I see. I stand corrected.

I very much appreciate your input on this idle issue!

I measured the dual ballast resistor today, Primary side is slight out of bounds, measured 1.9 Ohm (should be 1.12 to 1.38 ohm) and the auxiliary side measured 5.2 Ohm, which should be OK.

Not sure how the primary side 1.9 Ohm would show up when running at idle.