h3 hummer needs a tune up. What parts do I need and what will the cost be ? on 2006 Hummer H3

My Hummer will not start some times I have to let it sit 15 min then try to start it .I hear a wizzing sound like a loose belt.

Asked by for the 2006 Hummer H3
Not sure a tune up or routine maintenance will cause/fix your issue. When it does not start...does the engine crank over? the whizzing you hears this in engine area or towards back of the car by fuel tank area?