Your MFA is probably lying about the MPG. The air hose connection behind the clocks is probably split.
As for the two connections near the airbox, that sounds like its for your lights - are the front fogs working etc? If not, I would check the connection to the overrun cutoff valve and the pressure control valve, which is the only other thing I can think of near there.
In terms of general performance, next I would check your leads are in very good condition with no grey arcing deposits, then check your plugs are the correct spec and screwed in properly, then re-check your timing. Timing is critical.
After that you might consider a wet and dry compression test.