how do you test gm injectors on a 6.2?

Question

I am considering purchasing a one ton from a friend and I am wondering how to test them because it barely passed emissions leading me to believe there is a bad one.

Answer 1

Just because it didn't pass don't automatically start blaming injectors.
You need a more complete reason of why it didn't pass.
But non the less you check them the same way as any electronic injector.
I will assume ( making an azz out of you and me )
that you think one or more of the injectors are leaky.
Remove them from the engine and apply pressure to them ( like a rubber tipped air blow gun )
And see if they piss fluid on the bench.
You can connect small jumper leads to them with a limited current power supply to turn them on and off.

But heck it's G.M. they don't have crappy injectors....do they?