What's to know about starting a car? You've been doing it since you were a teenager. Although you might not have much to learn about starting your vehicle, you might have a lot to unlearn.

Changing technology demands changing techniques, and automotive ignition and fuel delivery systems have evolved considerably since you learned to drive. For example, if you're older than 30, you probably learned to drive on a vehicle with a carburetor--basically, a flap in a metal throat that mechanically mixed gasoline and air to get the engine running. By the late '80s, carburetors began to give way to electronic fuel injector systems. Nowadays, all vehicles use sensors to determine the engine and temperature conditions and computers to control the precise mixture of fuel and air needed.

Still, many people persist in starting their cars exactly as they were taught way back in their parents' driveway or their high school parking lot. In fact, by updating your starting techniques, you can stretch your engine's useful life, squeeze more miles from every tank of gas, and visit the repair shop less often. Avoid these four common mistakes when you fire up your machine to begin your morning commute.

Mistake 1: Pressing the gas while turning the key. Starting a car with a modern electronic ignition is a one-hand operation--no feet required. You just turn the key, without stepping on the accelerator. Let the engine's control module do the thinking for you.

"The computer sends a precise amount of fuel to each cylinder, based on readings it gets from sensors in the engine," explains Jim Lewis, administrator for the Club's downstate Approved Auto Repair shops. "By pressing the pedal, you're telling the computer that you want to accelerate, so it adds more fuel to the system. You could flood the engine."

Some owner's manuals advise pushing the accelerator partially to the floor if the first few starting attempts fail. Check yours for detailed advice. If you do flood the engine (that is, if it cranks but doesn't turn over and you catch a distinct whiff of gasoline), simply wait it out, advises Lewis. Try again after 10 to 15 minutes.

Mistake 2: Letting the engine crank for more than 10 seconds. After turning the key and holding it in the "Start" position, you should get the engine going in less than 10 seconds on even the coldest mornings. Holding it there longer--say, 20 or 30 seconds--while listening hopefully to the repeated rrruhr, rrruhr, rrruhr from under the hood risks doing serious damage.

"By cranking the engine for extended periods, you risk overheating the starter motor," says Lewis. "Eventually, it can burn out and need replacement."

Mistake 3: Revving the engine immediately after ignition. Revving the engine immediately after it "catches" does no good and may in fact do considerable harm. At the very least, it wastes gas. You simply feed more fuel into the system while going nowhere. Furthermore, experts point out that most significant engine wear occurs immediately after ignition, as the oil begins to circulate to all the moving parts. Racing the engine may exacerbate that wear.

Mistake 4: Sitting still for a lengthy warm-up. Today's engines really don't need extended warm-ups. Once the car starts, simply drive away, accelerating smoothly and slowly. A long warm-up not only reduces fuel economy but also pollutes more. Most cars burn between a half-gallon and a gallon of gas per hour while running at idle. During that warm-up period, you're getting zero miles per gallon--not exactly a bargain.

Meanwhile, your engine spews more pollutants into the air. Just after start-up, engines tend to run "rich"-- that is, with a higher proportion of fuel to air. That rich mixture produces dirtier emissions than a "leaner" mixture. Besides, as you drive, the catalytic converter reaches optimal operating temperature faster, better neutralizing many harmful pollutants.

Keep your speed down, at least for the first mile or so, and you'll maximize your mileage while minimizing wear-and-tear and emissions. That's getting your car--as well as your workday--off to the best possible start.