1989 Chevy Camaro Car Shutters when accelerating and then w

I have an issue with my car shuttering when you accelerate. I have replaced the fuel filter and it went away but had other issues, related to plugs, wires and cap. Replaced those. Car was low on fuel and filled up then car started sputtering again and while driving I goosed it and then it just died. I let it sit and then turned it over nothing. I used a multimeter to check teh Pump relay and Maf Sensor and burn off. Looked fine. I then removed an injector plug and tested it while it was being cranked got power was the #1 injector. PLugged the ijector back in and then did the same thing with the next injector by it and while testing it and having it cranked over the car started still running rough but started. Drove it home and then plug the injector back in and car died. Tested again removing a injector it started and then plugged it back in and died. Had all injectors plugged in and started it and it was hard but did start but ran bad. Rough, spuddering and shaking like it was about to die. Can anyone help me please. I have alot of money tied up in mechanic work and they dont seem to know what is wrong. Thanks.