What is wrong with my Range Rover? Crankshaft Position sensor?

What is your question?

Truck every morning and several times a day when starting has to crank several times before it will catch and run. Once or twice a month it will act like there is no starter and I have to unplug the battery and wait a few minutes then try again, and It starts up like its brand new. I have been told by a so called "mechanic" ( I say that because he is a friend and never went to school) that it is the crankshaft position sensor, but i'm unsure. I read on websites that a bad or going bad CPS will cause the engine to die while it is running. My truck never has issues driving just starting.