Rael

If it's going to be a long wait, I suppose you could just unplug the injector. That will trigger a couple more DTC's, which can be cleared later. Just keep an ear on the engine for mechanical issue's.

When you use the gauge, use one hand to align and steady the rubber line/end fitting, and the other to spin the gauge end. If #4 plug was loose originally, the threads may be suspect a bit.

Dave