Q: My car is a 2005 Acura TL. Twice this week the car suddenly jerked to the side for only an instant. It felt like one of the front brakes was suddenly applied. Then the VSA warning light came on - when I turned off the engine and restarted the car, the light did not come back on until this happened again a few days later. The service manager at Acura said he has never heard of this before. What do you think?

A: This is crazy! If the VSA (Vehicle Stability Assist) indicator illuminated while driving there will be a diagnostic trouble code stored. My guess is this was a phone conversation and the TL has not yet been checked out by a technician. VSA is a super smart and typically trouble free system that looks for a difference between driver intention and vehicle conditions to mitigate loss of control. Sensors track steering wheel position, yaw rate (actual vehicle turning), lateral acceleration (sideways force), vehicle speed, and additional inputs. If a slide or spin condition appears eminent, the antilock brake and engine management computers team up to apply individual wheel brakes and adjust throttle to reel in the vehicle.

On-board VSA diagnostics on this car are excellent. I counted 49 possible trouble codes for the system for such things as intermittent conditions or electrical noise in sensor circuits, loss of communication between modules, and many more rare but possible faults. I'd insist on having the TL scan tool interrogated at as soon as possible, before the trouble code(s) self erase. This is a rare problem, but serious, and with the right approach, is fixable.

Q: I am experiencing an awful burned oil/hot motor smell from the air vents when I am stopped in traffic or slow crawling in traffic. When I start going again the smell is completely gone. I have changed the cabin filter and used a $10 can of mold cleaner in the system that didn't work. I would be interested in your thoughts.

A: This sounds like a classic case of engine valve cover oil leakage or possibly leakage from another area that drips to the exhaust system. You didn't mention the type of vehicle or engine, but the odors listed are generic to just about any car or truck on the road. An engine has a valve cover for each cylinder bank - some engines have one, others two. Leakage from the cover's perimeter seal typically runs down to the exhaust manifold and burns, often without showing drips on the driveway. This is usually a harmless but annoying condition. Your ventilation system draws incoming air from vents at the base of the windshield. Should the fit or condition of the rubber seal along the back of the hood be less than perfect, engine odors are likely to be noticed within the cabin.

With the engine at operating temperature and odor evident, turn off the key, raise the hood, and carefully look for signs of feint smoke rising from any engine areas. If you can't spot the offending area, try again later with the engine cool (safer to be near), checking more closely for signs of oil leakage with a flashlight. Minor seepage from seals is normal, wet oil drips aren't.