Q: Regarding the random beeping of the 2014 Camry in your recent column, we had a similar problem. My wife drives a 2013 Mazda3. About two years ago I updated the computer chip. Not long after, for no reason, she would hear a "beep, beep, beep" coming from what sounded like the dashboard. We checked for dashboard lights, checked our cellphones, asked my mechanic, nothing. As my car was in the shop for a week, I was driving her Mazda daily. I noticed the beep would sound at the same intersection every time I drove by. It was the red light camera! Way to go, Roadrunner.

B.H., Palatine, Ill.

A: Well, what do you know? It is a bonus warning device to help you avoid tickets.

Q: I laughed reading your response to the beeping Camry. My 2015 Camry XLE also has the beep beeps and I have no idea why. Sometimes it happens if a bridge plate protrudes, jarring the car; other times it just happens for what appears to be for no reason.

G.T., Chicago

Q: Has the person looked for things on the front passenger's seat? It may not take much to set off the sensor and get an occasional ding because the seat belt is not attached. It confused me for a while.

B.F., Chicago

A: Hitting a bump while a package is sitting on the front seat certainly qualifies as a suspected culprit.

Q: What can I use to get rid of big globs of sap on the rear window and trunk? Don't want to try to scratch it off. I tried Turtle Wax tar and sap remover, but it didn't help.

Ken B., Glenview, Ill.

A: If you are sure it is sap, here are some suggestions. Soak a rag in the hottest soapy water you can handle and place it on the globs. After about five minutes, gently try wiping off the sap, but be careful not to spread it. If that doesn't work, soak the sap with WD40 (some people claim that hand sanitizer works almost as well) and allow it to sit at least 5 to 10 minutes and then gently scrape the sap with a wooden (Popsicle) stick. Another option is a plastic razor blade like those used to remove car decals. You can use a standard razor blade on the glass. Or, you could pay a professional detailer to do the job.

Q: My mom keeps raving about the improved mileage she is getting from having nitrogen put in her tires. She had it done to prevent a slow leak that she was told was due to aluminum wheels altering their shape over time and failing to hold a seal. Nitrogen sounds dangerous. What do you know about this?

L.S., Chicago

A: Nitrogen is perfectly safe. In fact, the air we breathe is nearly 70 percent nitrogen. It is so safe that some trendy bartenders are serving cocktails containing liquid nitrogen that creates a cloud in the glass and, for careful imbibers, a cloud from out of their mouths. We doubt that it improves fuel economy.

Bob Weber is a writer, mechanic and ASE-certified Master Automobile Technician.