[Desperado]

on my 87 fox i have notice lately that when i get on it it is fine but when i let off the gas i can smell a strong gas smell like it is really rich? was doing it with the 19 lbs injectors so i upgraded mass air and to 24 lbs injectors. any clue? want to solve this issue quickly. was running fine up till about 3 days ago. still runs great just has the fuel smell. sometimes it does it just comming to a stop from driving. have looked and can't see any fuel leaks from the tank to the injectors. also does it cold when i rev it. gas mileage has also droped. what can i check and how to check it. need this problem solved quickly please gas is killing me. i drive 140 miles a day and only getting about 145 miles to a tank now. the 24 lbs injectors are used and did notice when i shut off engine the fuel pressure drops from 35 to 20 instantly and the moves slowly to 0. with the 19lbs it did not do this it held 30 for awhile. but the smell was still there with the 19's it just started so i replaced them thinking it was them.

car specs.

87 stock short block and cam
mass air conversion
24 lbs injectors
equal length shorties
off road h-pipe
gt40 heads
1.7 roller rockers
frnder well cold air.
70mm tb
perfessional products typhoon intake
all smog stuff is still hooked up

fp is set to 39 vaccum line off 35 with it on.