I have a 87 chev truck, I've got lots of spark but no injector pulse and no fuel. When cranking the engine there is a drop of gas that comes out of the injectors but there's no power to them. Changed the fuel pump, the distributor cap, the throttle body and injectors, changed the computer, changed the complete wiring harness inside and out, pick up coil, and every censor on the engine. I drove it to my house 3 months ago and it hasn't started since. The only way it starts is if you prime the tuck, if you place gas in the injector holes, she will burn the prime then stop. I am a mechanic of 10 years and also have another mechanic of 25 years helping me and we can't figure this out anybody with any ideas please help!!!