Quote
The ECU grounds the injector signal to STOP firing in rapid succession... The constant ground is through the intake manifold ground wire.


Well i'm not sure about that, the wireing diagram would show the bodies of the injectors being grounded if there was such a "constant ground". That would be a pretty important thing to leave out. Also the injectors are mounted in rubber So any intake manifold ground doesn't affect them. I verified this with a VOM, there is no electrtical connection between the injector body & manifold.

Dave