Dave,
I ran a paxton on my 91 lx mustang with good results. I'd change your cam out for one with less duration. I ran the E303 cam, has 220 duration@ .050 . You are probably blowing fuel right though the engine into the exhaust.I would us the comp cams 268H, 218 @ .050. Also to pick up cruising fuel mileage you need to advance the timing to 36 degrees total and have a msd boost timing master to retard the timing 1 degree per lb of boost.The cam change will give you way better drivability and 5 mpg, the timing will give you another 2 to 4 mpg and way better throttle response.
Good Luck,
Perry.
