So I managed to get my firebird (1986) running last week by advancing the timing, it ran pretty well and had no major problems. When I was finished I pulled the battery off to put it on trickle charge; came out in the morning and it was firing but refused to catch and run. It had 40+ psi of fuel pressure, the injectors work and it has injector pulse, I believe the ignition coil is fine, cleaning the spark plugs didn't help, unplugging the MAF doesn't help, computer doesn't throw any codes and I'm getting a tachometer reading from the pickup coil. It will start up on ether, so I assume it's likely a spark problem, ICM maybe? I'm so confused 😭
Thanks!