Gettin' too old to care...
I'm not a kid anymore, and over the years I've known a handful of individuals who like to race their car engine a little and then immediately shut it off. They all claimed this was good for the engine--that it was "primed" for the next start and would start more quickly next time. I think this is not good for the engine, and does not make it start more quickly next time. I think that extra unburned gas could contaminate the engine oil. I just let the engine drop to idle speed, and then just shut it off. Please give me your opinion on this before I get too old to care.
RAY: You're absolutely right, Bill. Just let the car idle, and then shut it off. Giving the car extra gas doesn't help at all with the next start. And just as you say, the unburned gas seeps down past the rings and dilutes the oil.
TOM: This procedure is no better than drinking a large cup of coffee before you go to bed so that you'll be more awake the next morning. I've tried that, and it doesn't work either.