2000 Chevy Van FUEL PUMP

There are impellers inside you fuel pump that can degrade over time depending on its life and enviroment (i.e. type and grade of fuel, avg. fuel level). So more then likely there is nothing you can do to restore the functionality of the pump other then by rebuilding it, good luck finding a rebuild kit for a pump now a days. Generally the MAP sensor is located on the intake manifold, I have seen a V6 in my buddy's truck that was bracketed to the intake and connected with hoses to ports on the intake. It would depend on what engine you have. You can also refer to a Chilton Service manual that most local libraries have in their reference section, that is if you can't find it. It generally have 3 wires (see image).

(ABOVE)This is what your MAP sensor connector should be shaped like. (BELOW)This what your MAP sensor might look like., Not going to promise that this is exactly what it looks like. Just informational.