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The Red wire on all 6 injectors should show 12volts(battery voltage) with key on.
The Red wire is just daisy chained from one injector to the next on each bank.
So you have a broken Red wire if 3 injectors show "no power".
If you are using Noid lights, then "no power" could mean something else.
The Computer Grounds the injectors to open them, so the "other colored" wire at each injector won't show Ground except when engine is running and computer is pulsing the Ground to open the injectors.
In '93 a V6 will be Batch Fire injection, so 3 injectors will share the same "other colored" wire that goes back to computer.
Example: 3 injectors may have a Tan wire and the other 3 a White wire
So only 2 "injector" wires are needed back to the computer, but if one of these breaks..........it would effect 3 injectors.