Hello!
I would recommend to check feul trigger on that cylinder. Fuel trigger is the signal from the computer to the injectors. You would use a tool called a noid light. It simply plugs into the injector connector after the fuel injector is unplugged and should blink when the engine is cranked over or running. It looks like this.
Bob,
If the light remains on, then we will have to go directly to the computer and back probe the signal wire to this injector at the computer connector. If it still is pulled to ground, then you will have to cut it about 2 inches or so away from the computer and retest each side of the wires that you cut. (The one coming from the computer and the one going to the injector.)
If the one coming from the computer remains grounded, then the computer driver is holding the injector open. If not, then the problem remains ion the wiring harness somewhere.
ASE MASTER TECH
ADVANCED LEVEL SPECIALIST