When I try to start the car, it will crank very strong, but the car will not start. It will sputter a little bit. On the second try it will start right up. The car will run fine. When you shut it down for 2 hours or more, it will do the same thing. What could be causing this?

sounds like your head gasket is leaking and need replacing try turning the engine over with out the plugs in and see if any water comes of the plug holes or do a compression test on each bore to see if they a lower than the over bores hope it help you and you need a torque wrench if you going to do your self and now how to set up the timing marks on the crank and the cam .find them in car book

Locate the fuel pressure regulator and remove the vacuum line and start the engine, inspect, if vac port leaks fuel , replace regulator, provided your vehicle is equipped with a vacuum operated fuel pressure regulator.

have the fault codes read first and that will show the place to start

could be a problem crank/cam position sensor , immobilizer or ignition control module

it is the fuel pressure regulator

The engine is running very rich that is why the exhaust is emitting black smoke. The engine needs a tune up so the air fuel mixture is correct.

THE ONLY THING YOU CAN DO IS TAKE IT TO A SHOP SO THEY CAN SCAN IT FOR TROUBLE CODES. THAT WILL PUT YOU IN THE RIGHT DIRECTION.

change the crank sensor

My 2003 CTS would not start on the first, second or third try after filling the gas tank. Finally after several months of this occuring every two weeks a check engine light came on. It was the evac purge valve. Tom

Sounds like a vaccum problem, but I am not sure. It is not vapor locking on you is it? Maybe your fuel pump? A lot of possibilities.

you have a distrubidor problem