Q: I have a 2000 Ford Taurus that appears to no longer recognize the ignition key. The car has been sitting for four weeks while the local Ford dealer has unsuccessfully tried to find a replacement anti-theft module (the apparent culprit). Is it reasonable for automakers to say, "Sorry, we no longer provide that part. Try the junkyard?"
— J.B., Downers Grove, Ill.
A: Yes, it is OK to discontinue a part. The PATS (passive anti-theft system) module is one of those things carried in the parts system typically for about seven years. There may be one on some dealer's shelf somewhere, but it won't be easily found. We found a couple of used ones for sale online, and eBay may be another option.
Q: I own a 2013 Kia Sorento with 17,114 miles and have it serviced regularly at the dealership where we bought it.
When I recently took it in for service and a state safety inspection, I was informed that they had to do a BG throttle body service. I can't find anything about that in the owner's manual.
They also changed the cabin filter and filled the tires with nitrogen, and these three services cost me an extra $190. Are these legitimate things?
— J.K., Allentown, Pa.
A: They are legitimate services, but optional. Despite getting occasional hate mail from some tire dealers, I am still skeptical about paying extra for nitrogen inflation. (Brace yourself: I also drink tap water!) As the miles rack up, a throttle body cleaning may improve drivability and idle smoothness.
Q: My 2007 Mazda 6 makes a constant squeaking, rubbing, creaking noise and sometimes a clicking sound.
I feel it in the steering wheel and in the front end of the car or front wheels. Driving straight or turning, fast or slow, does not matter.
— B.S., Homewood, Ill.
A: All of those conditions apply to worn out constant velocity, or CV, joints. Typically, a boot is damaged, the lube leaks out and the joint wears out. There are four joints, two on each axle (half shaft).
Editor's note: Check out Motormouth's glossary of automotive noises that can help you and your technician identify the source of the problem.
Q: I have a 2009 Toyota Highlander and cannot find out when the transmission fluid should be changed or flushed. I do not tow and the car has 60,000 miles.
— S.G., Chicago
A: Toyota considers the ATF (automatic transmission fluid) in your Highlander a lifetime fluid unless you tow. But I would personally change it around 100,000 miles. It never hurts to be on the conservative side.
Q: I have a 2006 Buick Lucerne with 37,000 miles. For the past year and a half, I hear a swishing sound when driving 10-20 mph. It is possible that higher speeds mask the noise. I am the little old lady who drives to church and back.
— L.K., Glenview, Ill.
A: I have a hunch it is nothing more than a little surface rust on the brake rotors, which happens more often in damp weather between uses.
After driving for a while, the brakes eventually sand off the rust, but it will return.