Q. My friend and I both have Toyotas. On my car at 60 miles per hour, the RPM needle sits at about 2500 and doesn’t go above that range. My friend’s car, under acceleration, will go up to 5000 RPM. Why is there such a difference between these two cars?

A. Unless both cars are identical I wouldn’t expect them to be exactly the same. With that said, I would expect your Toyota to rev up above 2500 RPM under hard acceleration. At this point, I would bring your car back to the dealer and ask to compare it to an identical vehicle. This should determine without a doubt if your car has a problem.

Q. I took my car into the repair shop recently and when I got it back one of the headlights looked cloudy. I spoke with the repair shop and they wouldn’t own up to any responsibility. Did this happen during the service or is it something else?

A. It is very easy to damage a headlight lens by allowing a fender cover to drape over the headlight. This can typically occur during an oil change. Here, a fender cover is draped over the headlight with the engine running and the lights on, causing the headlight to overheat. In some cases the lens can be cleaned up, but other times the assembly needs replacing. I would go back to the shop and readdress the issue.

Q. I have a 2007 Buick LaCrosse and the anti-lock brake and traction control light will occasionally come on. I have had the local garage take a look at it, but the light is never on when I bring the car in. What can you suggest?

A. The most common problem is a faulty wheel sensor. Even if the light isn’t on, have the technician check for fault codes. Each sensor can be tested—the most common issue is a broken wire connecting to the sensor.

Q. At the end of March, I bought a 2010 Honda Civic and soon realized that the seat causes me sciatic pain. I’ve driven several cars over my 59 years and never experienced seat problems. I’ve adjusted the seat with no relief. Do you have any suggestions?

A. As someone who suffers from a similar ailment, I can relate to your pain. The only relief I’ve found is from cars that have decent lumbar support. In one of my cars, I added an inflatable lumbar cushion—the top seat cushion had a zipper, so I just slipped the inflatable bladder into the seatback. Other readers have told me that they’ve had luck with automotive upholstery shops adding extra foam to the seat.

Q. I have a 2003 Honda that has a six-cylinder engine and only 45,000 miles on it. The car was purchased in March of 2003. Should I have the timing belt replaced?

A. Honda recommends a timing belt replacement at 105,000 miles, or at seven-year intervals—whichever comes first. Since your car is now seven years old, it is time to have the timing belt replaced. As with your Honda, and many other cars, if the belt fails, the car will not only break down, it will result in some very serious and expensive damage.

Q. I have a 2005 Chrysler 300. When we get heavy rain, my horn starts blowing all by itself. The only way I can make it stop is if I pull the fuse out. I brought it to the dealer and they could not duplicate the problem. They finally agreed to change the fuse block, but sure enough the next time it rained, the horn went off. Since this never happens when the car is in the garage, it has to be related to something getting wet. Can you tell me if there are any technical service bulletins (TSB) regarding this problem?

A. I have checked AllData.com, the database that I use, and didn’t find any TSBs that fit the problem you are having. In the past, I have seen something similar—the airbag cover shrinking overnight and causing the horn to sound. Perhaps it is the drop in pressure and the cooler temperatures that occur during a rainstorm that are causing the same issue with your car. This becomes a relatively expensive problem since the horn switch is not serviceable separate from the airbag.