Fueling & Injection - Fuel injector troubles

My 5.3 vortec is missing on a couple of cylinders. My first process of elimination is to determine if the injectors are operating. on 6 of the cylinders, i can unplug the injector and the engine becomes noticeably stressed, but there are 2 injectors that don't affect the motor when unplugged. So that makes me think those 2 injectors are clogged or not functioning. for the sake of curiosity, I moved the 2 injectors to another spot on the fuel rail and the troubles continued with them. Any ideas?

I sent my injectors to Fuel Injector Connection to have them rebuilt. Their turnaround time is great, and it costs less than buying a new set of injectors.

FIC ...send them out if you think they are the problem.

or you can take your injectors off your fuel rails, grab a 12V battery and an air tank. connect the air tank to the injectors (or fuel rail if you took the whole thing off, usually much easier) (regulate the pressure to like 10ppsi or 40psi) and touch the battery terminals to the injector terminals. you should hear them hiss.

if they don't hiss they are not working properly.

One way to check if you don't have the air tank: disconnect the coils so there isn't any spark, then unbolt the fuel rail and lift it up so you can see the ends of the injectors. Have somebody else turn the starter a little bit. When I did that (before sending them to FIC), they just dribbled a little bit of fuel. Now, they mist instead.