does pressing and letting go of the gas save or waste gas?

well we know who the smart one is in your family, your mother. Any thing you do wastes gas rev the engine in nuetral, sit in the car in a store parking lot idling waiting for someone to go inside buy some stuff and come out. The best thing to do is not play with the gas pedal, leave it alone unless you are driving, there is no reason to sit there like a dufus and rev the engine for no reason. it makes you look kind of stupid too. best of luck, maybe you should listen to your mom more, and read more books.

I have no idea, I wish I knew. But I understand your question. I can READ haha.