when it "dies", have you tested for spark? if not, suspect the CPS of course, OR as you say your ECU may be the problem too, also check the cps voltage right at the ECU, make sure it`s getting the signal...
the MAP sensor either works or doesn`t, and even if it doesn`t work the engine will start but run like crap since the ecu can not detect the changes in manifold vacuum, it is unlikely that it will suddenly stop working and the work perfectly again later...