I need to take a deep breath before I get started. I just hate it when anyone becomes a parts changer and doesn't try to figure out the problem. It always wastes your time and you may never find out what the real problem. And in some cases, you can actually make it worse. I'm not trying to alienate you from this website and if you do end up getting upset by my words, please get mad at me, not this site. I'm trying to get you to slow down a minute, think about the problem logically and then solve it.
That out of the way, you need four things to make an engine work:
There is absolutely no reason to do anything else until you have verified those things. Meaning you would have to check spark at all 6 cylinders, preferably with a spark tester. Compression would also have to be checked at all 6 cylinders with a compression tester. You will have to test the fuel pressure, no way around it. Now since you replaced one injector, you really should replace the other. Even though you think it works, a worn injector will not work evenly with a new one. Luckily, you really don't need to check air. One thing I always do to check for vacuum leaks is to, with the motor running, take both hands and cover up the intake on the throttle body and see how the motor reacts to it.
Once you have done those basic tests, that would at least point you in the right direction.