Artickid,
If lube in the fuel made it run great, I'd buy one of those big jugs of PowerService additive at Tractor Supply and just make a habit of putting in a dollop every fillup. Ran great for 500 miles, that is about how long it takes for the CTD to whip through a tank. Marvel Mystery Oil is a good additive for lube purposes too, lots of people on the board are suspicious of it but I have had great results with it (fuel only) and it is famous for helping free up rings and other gunked-up parts.
If the pump is going to give up the ghost, the additives won't hurt and may prolong the life and let you postpone the $$$ until absolutely necessary. If the pump ISN'T ready to give up the ghost, the additives could save you a LOT of $$$.
dpyles,
What kind of hose did you use to replace the parts on your system? Only way a vacuum could get in the system, that I can think of anyway, would be for the hose to collapse under suction. I noticed that the replacement hose I got from the starter contact guy is pretty darned stout, presumably to prevent collapse. Maybe somebody else has some ideas.