If injectors are blocked and won’t fire any fuel through them, injector cleaner does diddly squat.
I’ve been successful at cleaning blocked injectors in the past.
I’ve found isopropyl alcohol rather good at cleaning fuel varnish from the external tip of the injector and it’s ports. I also use a 9V battery to activate the injector and pour a little isopropyl alcohol into it so the fluid gets inside. I then disconnect the battery. The alcohol doesn’t need long to dissolve/soften the crud so a minute later I grab my can of carbi cleaner. I wrap some electricians tape around the plastic squirt nozzle so it has a nice tight fit into the injector input port. I again connect a 9V battery to activate the injector at which point I press the carbi cleaner button. Doing such has been enough blow any softened gum straight out of the injector itself. I do all injectors. Last step is to put the injectors back into the engine and then run a can of injector cleaner within a tank of quality 98 octain fuel.
It’s a minor variant of the fast and easy fuel injector cleaning guide I found on YouTube, included below:
Probably the last comment is that if you’ve had blocked injectors, such can be caused by picking up some crudy fuel. In such cases it might be wise it flush the tank and lines clean. The issue can also be caused by using E10 after years of running 91 as the alcohol can soften the fuel varnish within the tank and lines so it moves and blocked the injectors which just reinforces that alcohol softens/dissolves fuel varnish. Other issues can be an actual fault within the injector itself which obviously would require injector replacement (as Holden is doing with many V8 injectors).
Just posting this as food for thought.