Q My 2006 Chevy Impala keeps flashing "Service Tire Monitor System." When I push the information button, it shows my right front tire is "flat lined", meaning no air in the tire. The tire is not flat. Ever since then, the same message appears every time I start my car. The service manager reset it but it continues to show up.

Why does this happen when there is nothing wrong with any of the tires? Is the government out to make money on maintaining this? I have checked for recalls on this and find nothing. Do you have any suggestions on how to cure this other than spending the $500 to replace all four monitors? How does a person reset this without going to the service department every time?

A Are you hearing black helicopters hovering over your vehicle? There's no conspiracy, only a mandated safety system to remind often-negligent car owners to keep their vehicle's tires properly inflated and warn them of any sudden loss of tire pressure while driving.

Is there a problem with the tire pressure monitoring system on your vehicle? Check for yourself. Turn the key on, but don't start the engine. Does the low tire pressure warning light come on solidly and stay on? If so, the system is working properly. If the light comes on solid, then goes out after driving awhile, the system is working properly and normal heat buildup is raising tire pressures above the trigger threshold.

If the warning light blinks for 60 seconds and then stays on solid, there's a fault in the system. A scan tool can identify the specific fault code.

There is also a system "relearn" procedure that requires a special tire pressure monitor diagnostic tool that may resolve the issue. If a specific tire pressure sensor has failed, it can individually be replaced.

Q My 2009 Nissan Versa was bought new and has only 13,000 miles on it. Since new, each time I go over a curving gutter while turning, say into my driveway or a shopping center, the front end makes a knocking sound and I can feel the vibration through the steering wheel. I have taken it to the dealer twice and they found nothing. The second time, the mechanic told me not to worry about it because the cars are built cheap and I should have bought a more expensive vehicle. If you could point me in a direction, I'd appreciate it.

A I'll point you to another dealer. Nissan issued a service bulletin for this specific problem. My Alldata automotive database pulled up bulletin FA11-001, reference NTB11-032, in March of this year. The solution is to install special tube-like insulators on the top and bottom coils of each front spring, and replace the strut mount bearings with updated parts. Your new car warranty should cover this update.

As for the mechanic's comment: You're joking, right?

Q BMW says I should use premium gasoline in my 2004 325xi, but I've heard from several sources that the ignition systems in cars will "adjust" to lower octane in regular fuel with no problems. Recently there was a 50-cent-per-gallon difference between regular and premium. That's enough for me to pay attention.

A For the past two decades I've owned vehicles requiring premium octane fuel. Modern engine management systems -- ignition and fuel delivery -- will adjust for lower octane levels to prevent driveability issues or engine damage. In some cases, performance may be compromised a bit.

With that said, for the past two decades I've used middle-octane fuel in these vehicles without problems or performance compromises.

Remember, the basic rule of thumb is to use the lowest octane fuel that the engine will run properly on.