Q: I was wondering if there’s a rule of thumb for shutting off a car while waiting in line at the bank or pharmacy or coffee shop, etc. to conserve gas. If I think I’m going to be idling more than a minute, like at the bank, I shut the car off. Does this make sense, or should I just let the car idle? Does it take more gas to restart the car? N.M., Elk Grove Village, Illinois A: I do the same thing, even on my motorcycle. Of course, there is an added reason on the bike. It gets hot down there. My rule of thumb is: If it seems like a long time, shut it down. It does not take more gas to restart …