musclemustang

hi, my dad has an 88 mustang gt that came out of a showroom he bought new in 88. it is still bone stock with like 170k miles on it. well here lately its been sitting awhile and i went up there to start it and it wouldnt harldy start it would crank over and over... well when it did finally start you couldnt hardly give it gas cause it would die and bacfire through the throttle body. I told my buddy about my problem so he said to unhook the vacuum line off the bottom of th map sensor then start it. It started up after that and run really good but tried to flood out it seemed and didnt want to idle, but still it would rev up good. we bought a new map sensor and hooked it up and still it wouldnt start and rwhen it did it ran horrible!! un hooked it an it would then start up and run decent but flood out and smoke. Any ideas ( Egr, 02, computer,) what next should i try??