Originally Posted by Arcrist
Ok, try this exercise and let us know how your engine is working after a little while.
Start your car, rev the engine while at a stop, and shut it off. Let the car sit for a few hours. There is unburned gas on the cylinders that can ruin metal.
What kind of metal? And who does this when they shut down their car?
I think your reaching for an answer, but we don't really know what the sound is unless he posts a sound file.