did you check the fuses? or the a/c ground that it usually tucked near the a/c relays (which hang right in front of the p/s pump)? all of those could cause the a/c problem. as for the mpg... what ecu are you using? and how are you driving? if you beat on it constantly (who drives a b16 and doesn't?) than you're gonna get 17. also do you have one of those aftermarket fuel pressure regulators that everyone thinks are cool because they're purple?