Q With only 12,000 miles on my tires, I'm told they are cupping and I should have them replaced. Since the tread is good with the exception of the "scalloping," do I need to buy new tires? I bought the car new three years ago and thought I would not need to be concerned about buying tires for several years.

A Were the tires rotated every 4,000 to 6,000 miles? I suspect not. With today's longer oil change intervals, it's a good idea to rotate tires at each oil change.

At this point, you could rotate the tires and live with the situation for the remainder of the tire's life. The only concern, as long as there's significant tread across the entire face of the tread, is noise and continuing wear from the cupped pattern. And no, rotating the tire now won't wear the cupping pattern off the tire.

The other possibility is to have the cupped tires "trued," where a special machine shaves the tread surface down until it is even again.

Or, buy new tires and remember to rotate them every oil change.

Q My daughter bought a 2003 Honda Accord about a year ago. It has 123,000 miles on it, runs great and is very dependable. The past three months, she noticed unusual oil use. Between oil changes she has to add 4 to 5 quarts of oil. Our mechanic did not find any oil leaks. It does not appear to burn oil from the looks of the exhaust. Someone suggested changing the PCV valve, but the oil is still disappearing. Any ideas?

A Assuming the engine still runs well, there are several possible explanations for the sudden, excessive oil consumption. An oil leak from the valve cover or cylinder head gasket might be dripping onto the hot exhaust manifold and burning off -- typically there would be a noticeable smell from this. A blocked or clogged positive crankcase ventilation (PCV) port or leaking PCV hose could allow the crankcase to pressurize, forcing oil into the combustion chambers, where it would burn. The uniform distribution of the excess oil in this case might not create a noticeable amount of smoke from the exhaust. And finally, significant internal wear -- oil control rings, piston and cylinder could allow excess oil into the combustion chambers.

With the engine warmed up and idling, slightly pinch the PCV hose. You should hearing a click sound from the valve each time you pinch it.

Since oil is relatively inexpensive, it's worth a little more detective work to identify the source of the oil loss before giving up on the vehicle.

Q I have a '96 Buick Park Avenue with 154,000 miles on it. When I accelerate quickly or go up an incline, there is a slight vibration. My mechanic and the dealer tell me the torque converter clutch is going bad and it would be too expensive to replace. Is there something else that could cause this?

A First, confirm the diagnosis yourself. When you're accelerating and feel that vibration, maintain the throttle setting with your right foot but gently depress and hold the brake pedal about half an inch down with your left foot. If the vibration stops, then returns after you release the brake, the torque converter clutch (TCC) is slipping. The typical cause for this is worn seals or grooves in the torque converter hub. A leaking torque converter clutch solenoid in the transmission -- accessible through the transmission side cover -- could be the culprit.

Is there a cheap fix? First, add the correct Lube-Gard additive to the transmission fluid. If that doesn't help, you could invest in a complete fluid and filter flush and refill. Add half a can of SeaFoam Trans-Tune before and after the fluid change.

I've heard of clipping a wire to power down the solenoid without triggering the check-engine light so that it doesn't try to engage the TCC. The transmission would still operate normally, but without the TCC feature.