Q. When driving in my 1994 Bonneville, I hear a clunking noise. The noise happens when I make a right turn, and it sounds like it is coming from the rear. What do you think it could be?

A. The noise could be just about anything from a loose/broken muffler to a worn control arm bushing to a broken rear sway bar. Typically a technician will put the car on a lift and look for worn, loose or broken parts. You should get the car in for repair as soon as possible; depending on what is wrong, this could be a safety issue.

Q. I was listening to your radio program while in Boston, and I heard you extolling the virtues of the Jaguar XF, describing it as one of your favorite cars. I like the car but I am also considering the Mercedes CLS. If it were your money, which car would you buy?

A. In the spirit of full disclosure, I haven’t driven a CLS in a few years, but in my opinion, the XF is the winner in this comparison. Both cars have stylish good looks that can only be appreciated in person, and the performance is similar. The interior space is about the same, and the overall build quality seems about equal. I found the ride of the XF to be more comfortable than I remember on the CLS. The CLS has the edge in an overall solid feel, which Mercedes does better than any other manufacturer. My biggest complaint with the Jaguar is the tedious and cumbersome navigation, audio and climate control system. Although for the more than a $10,000 difference in price, I can put up with them.

Q. I sent an email to Honda concerning a problem with the air conditioner of my new Honda Fit. The problem has been described as a “condition,” not a problem. The service manager told me that whenever you push the accelerator more than 20 percent the A/C shuts off. Any suggestions?

A. Many cars, Honda included, will shut off the air conditioner compressor under acceleration. In Honda models and many others, this will happen under wide open throttle conditions. Because most people don’t drive with their foot to the floor for extended periods of time, there is little or any change in the air conditioning performance. The reason that the A/C shuts off is to help maintain performance and improve fuel economy. I have sent an email to Honda requesting additional information and heard back from Chris Naughton, Honda’s east coast public relations manager. Chris confirmed the operation of the A/C system and tells me they don’t know of any problems with this model or any other Honda model.