TPS - Throttle Position Sensor
The problem with the MAP sensors is that most fuel injection setups cannot inject different amounts of fuel to different cylinders. So if you have one throttle blade that's not opening quite as much you get less air to that part of the manifold but the fuel level doesn't change -- you go rich. Or if one throttle is open further then you get more air and those cylinders go lean.
You could add more MAP sensors without a whole lot of trouble but the computer wouldn't be able to make use of the extra information. So what EFI proposed was just to make sure that the throttles were sycronized. That way even though the MAP only measures pressure in one intake section it doens't matter.
