I don't like to do that b/c you might have a flooding problem within your combustion chamber and possiblity of not able to start your engine right away. Why don't you just look at your tach and see where the needle is located. Anything above the "0" mark, you know what that means. I did this numerous occasions b/c my engine is so smooth and vibration-FREE. Envoy and TBlazers have a safety switch incorporated in their ignition switch so that one can't engage starter motor if the engine is on b/c GM claims that their L6 is so smooth and vibration-free (read that from their brochure). My pilot is even smoother than TBs and Envoys (test drove them). Matter of fact, 100 times better.hubby45251 said:How can you prevent it? Hit the gas, if the tach moves.....your good to go, if not, turn the key.