Ford Repair: 1989 Ford Mustang 5.0, mass air sensor, fuel pressure regulator

Question
I have a 1989 Mustang 5.0L.  Recently I have experienced a problem.  The car runs fine at most normal speeds.  If I floor the throttle, the car bogs down terribly and shakes as if starving for fuel until I back off on the throttle.  Should I try to hit passing gear to pass on a road, I'm dead.  I've upgraded to a better fuel pump, new injectors, new TPS, and IAC valve (suggested by my mechanic) and still have the problem.  Any suggestions?  

Answer
Jeff-

  I'd check the vacuum lines...make sure there are no holes or loose connection/lines pulled off and also replace your fuel pressure regulator.  The regulator would be my first guess, but checking vacuum lines is free and relatively easy.  You might also think about cleaning out your throttle body with some carb cleaner and making sure your mass air sensor is checking out ok.  Hope this helps.

Steve