Q: My 2020 Chevy Blazer has an issue with the gas gauge going up from half full and increasing as I drive, then it drops to empty. I brought it to a dealer, only to be told, “We cannot replicate the problem with our diagnosis systems.”

I think it is the fuel sending unit or sending wiring or fuel pump. The Blazer is still under warranty. Could you help?

A: The technician should be able to check the voltage on the fuel level sensor circuit and may even take a snapshot with his diagnostic equipment after filling the tank. I have a hunch the problem is with the sensor itself. It is part of the fuel pump assembly, so they get replaced together.

Trust battery tester

Q: My mother is elderly and has a 2021 Toyota RAV4. She lives in northeastern Wisconsin, where the winters are cold, but I’m not near enough to give her a jump-start if the battery dies. I’d like to replace the battery before it dies at an inconvenient time. How reliable are the battery testers that dealers have? Is it safer for me to replace the battery every so many years, or should I just wait until the dealer says it needs to be replaced?

A: The professional battery testers are very reliable. Batteries have become quite expensive, so routine replacement would be costly. Instead, give your mom a portable jump-starter power pack. It will fit in the trunk or even the glovebox and costs under $100. No need for jumper cables. Any good Samaritan can quickly get her on the road to purchase a new battery.

Bad vibrations

Q: Recently, the steering wheel on my Nissan Rogue with 60,000 miles has begun to vibrate when the car accelerates. Any idea what might be wrong?

A: I have a hunch there’s a problem with the torque converter, especially If the vibrating stops when you tap on the brake pedal.

Too much is better

Q: VW has a mileage interval for changing spark plugs. But they also have a time interval requiring change every six years regardless of mileage. I would not think modern plugs would degrade because of age. What would be the reason for the time interval?

A: It is typical of German automakers to require more frequent care for many things. But you’re right, spark plugs do not wear because of age. However, as I have said before, over-maintaining is a heck of a lot better than the other choice.

Bob Weber is a writer, mechanic and ASE-certified Master Automobile Technician. His writing has appeared in automotive trade publications, Consumer Guide and Consumers Digest. Send automotive questions along with name and town to motormouth.tribune@gmail.com.