Hi! I have an 85' Chevy g20 350 motor. I've been having misfiring issues and I brought it in to be looked at and they suggested I change the cap and rotor. Did that it was running a little more smoothly. Was driving around today, parked then went to get gas(got midgrade instead of regular), made another 2 stops. On the way home it stalled out and wouldn't start up again. It's cranking but not turning over. Fuel is good, there is a spark, any idea what else I should check given these issues. Thanks in advance.