RAY: This is from my teen driver series and it's also automotive in nature. This was sent in by a fellow named John Anderson from Superior, Wisconsin, and I'm sure he won't recognize it at all. He writes:

'A few years ago, a friend of mine was a service manager at the local Toyota dealer. He had a customer with a fairly new Camry who complained regularly of lousy gas mileage. He was getting between half and two-thirds of what it should have been.

'The shop checked everything they could think of, from dragging brakes to low tire pressure, to slipping transmission. They did a computer analysis of the engine. They checked for a faulty thermostat and all the other bogus stuff that they hear all the time on Car Talk that could contribute to bad gas mileage.

'After several visits, they could find nothing wrong. They even interrogated the owner, you know with the bright lights like they do in the police stations.

''Do you drive above the speed limit?'

''No! No! Never,' he says.

''Jack rabbit starts?'

''Never!'

''Excessive idling?'

''Never, never, never, I swear I never do these things.'

''Do you have a teenaged son who drives the car?'

''Well, yes, but very little. Because the car is so new, I've limited his driving. In fact he uses it just to drive to his friend's house to study and play the oboe. His friend's mother has told me it just sits there in the driveway for hours on end. If they do go anywhere, they use her son's car.''

After listening intently the service manager suggested the customer go to the parts department and purchase an item and install it on his car himself. The customer could easily do this without even opening the hood. The item costs less than $20. The customer did it and of course it worked perfectly! His mileage was restored to normal.

What did he buy?