Christopher:

The good news is--you are very close to solving this! It seems clear that the problem is in the injector rack assembly at some point. that limits it to the piping of the rack, the fuel lines running from the rack to the injectors, or the injectors themselves. I don't recall that you mention replacing the fuel lines, but if you didn't they could be rotting on the inside, sending debris in to clog the injectors. If gas sat in the piping, you could have had a minor varnish build-up that washed loose with new gas and affected the injectors (highly unlikely, I would think). You could, though, have trash from a deteriorating fuel line in the piping. If all those areas are clean, the injectors could be the wrong part, as you suggest, or could have faulty seals. If you haven't already done so, I would disassemble the rack and be sure you have good flow through all the lines, replacing any fuel lines that are still old. Then do a flow test on the injectors (if you can get the engine to run, that is!). I followed a procedure that I read on this board (I think) a long time ago. Pull one injector and replace it with a stopper, being sure it is not small enough to get sucked into the cylinder. Start the engine and observe the spray from the injector. Measure the fluid output of the injector. Be very careful--spraying gas and a hot engine are an interesting combination! The spray should be symmetrical and the output should be very close across all four injectors. You may then want to compare the output to that of one of your known good injectors. My car sat for 10 years before I bought it. The injectors didn't work. I pulled them, put light pressure on the needle that stops the flow to break it loose from being varnished shut, then soaked the injectors in gas. Replaced the seals and they have worked fine for 2 years now.

Good luck!