Sputtering issues 1992 caprice 5.0
 

so I have a very frustrating issue at hand, recently acquired a 1992 caprice with 80k on the Odom he said he was haven’t issues keeping it alive so I replaced the plugs,wires,fuel filter,ect sensor,gas cap,thermostat and it ran ok but now it wasn’t to cut out every now and then under load or sitting at a stop light, I’ll tap the ecm ( which I just replaced the other ecm had the same issue but kept the same prom)and it kicks back in to shape. I don’t want to play the throw parts at it game so I’m looking for some help. Any advice?