This is for mpfi.
You'll need:
Injectors
New o-rings for install
Syringe
Carb cleaner
Injector plug
12v source

Do at your own risk.
You'll need a syringe that fits on the o ring of the infeed side and fits the little tube of the carb cleaner on the other side

Set everything up like the picture below. Just keep in mind you don't want the injector on to long (10-15 sec max).

So get everything ready then plug/switch on 12v. Immediately push on carb cleaner. Make sure syringe is secured tight or you can hold it in place, but this creates a lot of pressure so beware. It'll look like this.

Then reinstall with new o-rings.