Code 31 Stalling Problems

[87vert]

when you accelerate it will stumble and die if you keep on the throttle. It will do this unless you barely push in the throttle then you can go as fast as you want if you accelerate slowly. When it cuts off usually I will get code 31. I am getting 5 volts to the Map sensor. With the Key on engine off Im getting about 4.2V which according to the haynes manual is where it should be between 3.8 and 5.5. How ever when I turn on the motor (giving it vaccum) it will drop to about 1.2-1.5 According to the manual it should only drop by 2.3-1.5 volts. I got 2 more MAP sensors from the junkyard and they all do the same thing. Maybe there all bad. I dont hear any vaccum leaks. I cleaned out the EGR valve but that didnt seem to make a lick of difference. I havent pulled the TB off yet to clean it but have tried spraying it down and then tapping the throttle.