Before you pull anything apart, try this.
Start engine, have appropriate wrench handy for injector nut, 11/16 or 17 I think.
With engine running, crack nut until you see fuel
spurting. Engine should lose RPM
If you do that and have no change...I would suspect the injector. If you have a good spare injector, pop it in and see if there is any change.....Do not touch the tip of the injector with your fingers or let it bounce off the deck