Perhaps the greatest myth about idling is that it's good for the engine. The truth is that excessive idling can actually damage a vehicle's engine.

Contrary to popular belief, idling is not an effective way to warm up a vehicle, even in cold weather. The best way to do this is to drive the vehicle. Today's electronically controlled engines allow you to drive away after only 30 seconds of idling, even on the coldest winter days.

Excessive idling can be a problem for a few reasons:

* First, since an idling engine is not operating at its peak temperature, fuel combustion is incomplete.
* As a result, fuel residues can condense on cylinder walls, contaminate oil and damage engine components. For example, these residues tend to deposit on spark plugs. With more engine idling there is a drop in the average plug temperature and accelerated plug fouling. This can increase fuel consumption by 4 to 5 percent.
* Excessive idling can cause water to condense in the vehicle's exhaust. This can lead to corrosion and reduce the life of the exhaust system.

There's another good reason for motorists to drive away soon after starting a vehicle. The engine is only one component of a vehicle. Other parts, such as the wheel bearings, steering, suspension, transmission and tires, also need to be warmed up, and the only way to do that is to get the vehicle moving.