I would probably go about it a little redneck, but here is my 2 cents. If you think you are starving a portion of the engine, or the entire engine for fuel, remove the injectors from the cylinders, and connect them to empty Mt. Dew bottles with some tubing. Bottom line, make the injectors spray into the bottles, and not the cylinders/intake manifold. Then crank the car, or better yet, have someone else crank the car over and you watch the injectors. they should all spray an approximately even amount and give the same pressure/spray pattern. If they do not, look in the book and find what the spray pattern should look like, then replace/clean the ones that do not match. As far as fuel pressure in the line before the injectors, there are aftermarket pressure gauges that you can install. A few questions for you: Has this car sat for an extended period of time? Is there a chance that something got into the tank that would clog the sending unit? When it is running do you see any fuel drips or leaks? If there is an inline filter, is it installed the correct direction, and is it clean? Personally I would take a trip to the store, get the haynes manual, and then start with the easy cheap stuff and move on up from there. Again like I said...might be a little redneck, but its just my 2 cents.
My Corvair doesn't leak oil...It just marks its territory!