Yeah, MAF sensor sounds like it, but could be a coolant temp or air intake temp sensor problem(?). Either way, probably an a/f issue.
Try tapping on the MAF body with a screwdriver handle and see if it reacts. Um, just for giggles, try checking the firing order. Good luck.
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Capri306, Moderator, The Mustang Works Online
1979 Mercury Capri, 5.0L -- C4 -- 2.73
1987 Mustang LX Notch 
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