I am working on a 1997 F150 4.6 automatic 4x4. The truck starts and continues to run, but when I disconnect the injector wiring from injector No.1 &4 there is no rpm drop. The cylinders do have good plugs and wires. they are receiving 12 volts at key on. I quickly supplied just a flash of a ground to injector No.1 and it did let the cyl, fire. The harness is in good order with no sign of bare or possible break in the pulse lead.