Where is the camshaft sensor located

My van keeps stalling while driving. Right before it cuts off the oil light pops on. When it cuts off it will turn over but will not catch. Can only drive maybe a mile before it stalls. Have to sit for about twenty to thirty minutes before it crank again with no problem. Once it stalls all components still work though. Someone said it is the camshaft we need but do not know where it is located. Pictures, illustrations will be helpful. Thanks