I have seen the mass-air get sticky after sitting for a while, the best thing to do is what 930zx stated. It is a little bit of a pain to run the old gas through though. I got my 86' that had not been driven in almost a decade with a half a tank of 93' from 98'. So I drained the tank, replaced fuel and attempted to start. Long story short, I ended up running the car on starter fluid until it passed the new fuel through the distribution block, took a long time, so dont get discouraged while you do yours.
86' 930/GT-40R Sold
94' Rustang GT daily