Dayton Daily News

Q: In a recent column there was a question about Dynamic Laser Cruise Control on a Toyota Sienna XLE. In the column you included a quote from the reader that stated that it is an expensive but useless option. I strongly disagree. I also have a 2004 Sienna with the laser control system. I love it. I drive from Wisconsin to southern California every fall and return each spring. The system is very reliable and the added safety is its strongest point. You can’t rear-end another vehicle, even in fog. I’ve tried and it works. Also, if someone cuts me off, an alarm sounds and the brakes apply automatically. In addition to this, the inability to use the system in snow and rain is no big deal because you probably should not use cruise control in those conditions anyway. What are your thoughts? D.P., Amery, Wis.

A: The reader to whom you refer is very dissatisfied with the cruise control in his Sienna. He uses the system in snowy and wet weather, and the system fails as a result of sensors that are obscured by the conditions. You are very satisfied with the system and understand its limitations. You probably read your owner’s guide that explains use of the system and its limitations. You also are correct not to use the cruise control when roads are slick in snow, ice and rain. These conditions may cause a loss of traction that could cause an accident. The use of cruise control under these conditions may cause wheel spin and make controlling the vehicle extremely difficult. Also, sometimes during freezing temperatures bridge surfaces may develop ice. If the cruise control is controlling vehicle speed, watch out — the drive wheels can lose traction and send the vehicle right off a bridge.

Diagnostic test may find cure

Q: The engine in my 2001 Acura MDX with 53,000 miles runs very rough when the RPMs are just below 2000. If I accelerate or decelerate, the engine runs and responds well. At this time there are no warning lights. Do you have any idea what’s wrong? K.C., e-mail

A: It wouldn’t hurt to have a computer diagnostic test performed. You state that there are no warning lights on right now. This gives me the impression that a light has shined in the past. There is a good possibility there are diagnostic trouble codes stored in the computer. A test might find misfired diagnostic codes that will guide a technician to the source of the trouble. What needs to be done to cure this condition may be as simple as replacing the spark plug wires and spark plugs or a little more involved such as cleaning the exhaust gas recirculation ports and replacing the intake manifold gasket. Tests will set the course to repair.

Brake work leads to shimmy

Q: Recently I took my 2002 Buick with 75,000 miles to a dealer for new rear brakes. The car tracked perfectly before the repairs, but afterwards the car had a shimmy. I returned to the dealer where the rear tires were balanced for free. Despite this, the shimmy continues. What’s the cause? J.R., West Saint Paul, Minn.

A: To determine the cause of the shimmy, explain to dealer personnel when you feel the condition. Perhaps it only occurs when you apply the brakes. If this is the case, it’s possible that one of the rear brake rotors is not true. If so, it may need replacement or maybe it needs to be machined if there is enough metal remaining to machine.

Or perhaps shims need to be added to the rotors. If you feel the shimmy driving along at a certain speed without touching the brakes, it’s possible a tire is out of balance in the front or back. It’s also possible there is a problem with one of the tires, such as a bubble or broken belt internally in the tread. If such a condition exists, the afflicted tire should be replaced.