I had the same issue when switching to Petronix ingnition. I was able to verify it was my coil by running a jumper wire from the empty small post on the starter solenoid to the hot side of the coil. This enables a full 12 volts to the coil only while cranking. My old coil and harness had to much resistance for the ignition module to fire. I ended up changing out the coil for one recommended by Petronix and life was good. I would crank it over when hot and it was crank and crank and when I let off the key it would fire but not continue to run. The jumper wire is a old mercruiser thing. Might be worth a shot.
2003 Supra Launch 22SSV
1986 Ski Natique 2001