I have an 03 Sierra 2500 HD and it will often not start after I drive it a while then stop. When I try to restart, the engine will crank, I hear the fuel pump, but it won't turn over. 10 or 20 minutes later it usually starts. Any idea? I saw somewhere that the crankshaft position sensor might cause this but I'm not sure how likely this is or if I should be looking for something else.
