When the 2002 Chevrolet Malibu doesn't start, generally speaking it means something's amiss with the car's electrical or mechanical systems. Some diagnostic work may help discover the problem.
Make sure the Malibu's parked on a flat and stable surface and the transmission is in "Park." If the car's on a slight incline or decline, set the parking brake and chock all four tires for safety's sake. Pop the hood, prop it open and turn the key in the ignition to the first setting, which will turn on the electrical system.
Turn the Malibu's headlights on. If they come on, you can assume nothing's wrong with the electrical system and concentrate on the engine; if the lights don't come on, check the battery. Look at the positive (red) and black (negative) battery cables: if they're not attached, secure them to the terminals. If corrosion is present, use a wire brush to scrub the corrosion away. Remove the battery and replace it with a new battery and try starting the car.
Use the voltage meter to determine which --- if any --- spark plugs may be going bad. If you find that one or more plugs are indeed underperforming, replace all the plugs, not just the bad ones. This will help you ascertain spark plug problems in the future should the car not start again. You'll need to have the car towed to shop so a mechanic can determine if the Malibu's alternator is bad.
Check the amount of oil in the engine by checking the dipstick. If the stick registers lower than the "Add" or "Fill" line on the stick, pour at least 2 quarts of 5W-30 oil into the engine. The Malibu, like some other cars, won't start if oil levels are too low, as driving the car with too little oil may cause engine seizure. Replace the starter with a new one, available at your local auto parts dealer or Chevy garage.
Pour at least 2 gallons of regular unleaded gasoline into the engine if the Malibu's fuel gauge is registering less than a quarter tank of fuel. In some cases, the fuel sensor can go bad and give an improper readout on the gauge. By filling the car with as little as two gallons, the sensor may be able to correct itself temporarily, although you'll have to have a mechanic fix the sensor problem.
