DEAR CAR TALK: My husband drives a 6-cylinder 2004 Buick Rainier. It’s blue – my favorite color – and matches the decor of the house. He got this SUV from a friend who buys totaled cars and fixes them for re-sale. This is the best one yet, and he wants to trade it in for a Jeep!

Of course, one of the boys at his weekly gathering called Car Night has a Buick SUV and agrees with him that it’s a “pig” and should be traded.

Anyway, he keeps tracking his gas mileage at every fill-up. Recently it has gone down from 17-18 miles per gallon to 16.6. I told him that wasn’t much and he just needs a tuneup. “Spark plugs, dear.”

Last night on our way to a fish fry he said it again for the umpteenth time, “I’m trading this in.” I calmly answered, “Spark plugs, air filter and gas filter, dear.”

My problem is, I am afraid that someday soon he will come home driving something that I won’t like again, when simple maintenance could solve his obsessiveness with gas mileage.

What do you think? – Sharon

RAY: I think you’re right to be afraid, Sharon. He is going to show up one night with a Jeep. I can pretty much guarantee it. I also predict that the Jeep is going to get 13 miles per gallon, and he won’t care.

He hates the Buick. His friends are mocking him for driving it, and he can’t wait to get rid of it. All the complaining about gas mileage is just “preparing you” for the inevitable trade-in.

And I think you should just let him do it, Sharon. Remember, there are worse things husbands can decide to trade in. In the interests of marital harmony and good will, I’d say to him, “Frank, you know I like that Buick, but you should drive whatever makes you happy.”

Then here’s how you get your revenge: Every week, when he’s not looking, you siphon a little gas out of his Jeep and put it into your car. Take out a little more each week.

He’ll be completely confused as his mileage drops from 13 mpg, to 11, to nine.

When he gets down to seven mpg, you can come clean and tell him about your practical joke. If he’s got a sense of humor, he’ll be impressed with your ingenuity and you guys will have a good laugh together.

If he doesn’t have a sense of humor, he’ll divorce you, and then you take your half of the assets and buy your own Buick. Good luck.

Got a question about cars? Email Car Talk’s Ray Magliozzi by visiting the Car Talk website, www.cartalk.com.