1992 GM 350 TBI motor, 1 injector quit working. Tested both wires with noid light. Gently tapped the injector housing and the other injector started working. Got a fuel pressure regulator rebuild kit and 2 of my spare injectors. Started up just fine, then the next day the injectors quit again. Tested with a noid light and they flashed like they should. Tapped on the injectors and started working again. Figured it must be 20yr old spare injectors. Got 2 brand new injectors. Again fired right up after the new injectors where installed. Next day, not working again. Cranked, then "jumped" the injector and no clicking or spray. Tapped on the injector and then jumped it again and it clicked and sprayed fuel. Soooooo........ why are the injectors sticking? I have not checked fuel pressure, I know I have fuel pressure but just haven't put a guage on it to see if its in spec. I also changed the injector housing, just to rule out anythng odd. And changed the fuel filter.