cam shaft sensor

i recently went to start my truck and it wouldn't start. i have new plugs, wires, distributer cap, fuel pump, mass air flow sensor, fuel pressure regulator, cam shaft sensor and crank shaft sensor. now it runs but it dies. like its running out of fuel. if i un hook the mass airflow it idles at 2000rpm's.
but as soon as i hook the mass airflow back up it has a lot of trouble idleing.
hooked up computer and it say's cam shaft sensor malfunction. i asume that my problem is in my distributer because of this but then why does it idle high with no problem when i unhook the mass airflow? somebody plz
vehicle is 1997 silverado/ 5.7 vortec

Welcome to AF. First of all what truck is this, second post it in the appropriate forum for the model and year, below.