Diesel engine, on tick over, revs surge, then engine dies.... fuel stavation or air leak ?????

Could be either. What vintage and type of system is this? The newer 'common rail' stuff is a lot different than the older mechanical or electro mechanical stuff we had back in the 1900's. On old stuff lack of fuel usually won't cause a surge or smoke. Air in the fuel will cause surging and smoke. Newer stuff you would usually start by checking for trouble codes. It could be a sensor that is sending bad info to the computer.

Fuel. That is unless your talking about air getting into the fuel system and making it lose prime.