When cold engine starts on the first attemp 80% of the time, when warm its about 60-70%. Sometimes it take 2-3 attemps to start. But on the second to last attemp the engine will fire very little and then knock off.
So far I replaced the distributor, spark plugs and wires, boost sensor?, fuel pressure regulator, and checked the injector ohms and fuel pressure at the engine with the old pump. After replacing the fuel filter it started fine for a few days, after replacing the fuel pump it started fine for a week. Thus making me believe it’s a fuel issue. So I added check valves to the fuel line at the engine, both the supply and return lines. And still few days later it’s back.