Oil injectors, aux port actuation

[sv51macross]

Update:

Was able to do a bit more disassembly. Found that the exhaust manifold nuts were above the heatshield...after breaking the heads off the top two bolts. At least I can now ground it proper and get some fuel economy back!

-That aside I removed both manifold injectors and spritzed some brake cleaner through the vac nipple, injector orifice, and the banjo bolt orifices. Did the blow/suck test and one I could both blow and suck through the vac nipple, the other would blow through and allow a little air to suck through. Haven't tested the housing injectors, but it seems that only one of the four injectors is actually working.
-Now, could it be a loss of vacuum? Perhaps the hose that plugs into the intake snorkel isn't sealing? Or do I have three bad injectors? (If the latter, then f***-it, I'm buying a container to pemix 2-stroke oil until I rebuild/swap the engine).