Quote Originally Posted by chris_d
Turn it off.

Read the car manual(if you still have it though), car manuals contain information such as these. Some samples of instructions in car manuals include: "Do not leave the engine idling for long periods of time.", "If you are going to idle the engine for longer than 3 minutes, turn it off and save gas"... and so on....
wala na po yung manual nung i-acquire ko car (2nd-hand) about 5 years ago.