Why would my 2002 chevy malibu ingnition lock up?

SOURCE: 2002 chevy malibu won't start

Does the starter make any noise or click when you turn the key to start? If it does not, chk. battery could be bad, and battery cables could be loose or corroded. If there good and clean and battery is good try tapping starter see if it will turn and start if it does or still clicks starter bad. It could be ignition switch if it does nothing at all, but if it clicks most likely its starter.

SOURCE: Cannot locate horn for a 2002 Chevy Malibu

it's between the radiator and the grill, there are two of them.  Have you checked the horn relay?

SOURCE: thermostat on a 2002 chevy malibu

Which engine>? There are a few different engines available.

SOURCE: how do you change a lock n key ignition switch on 1998 chevy 6 cy

STOP. STOP. STOP.
I WILL POST WITHIN THE HOUR.
In the meantime, click here for a few things you need to know before even considering working with undeployed airbags.

Mike

SOURCE: Chevy 2002 Malibu ERG valve

Symptoms of a bad EGR valve are usually stumbling idle or the engine stalling when the car is warm (normal operating temperature). Find the EGR valve and locate the vacuum line attached to it. Start the engine cold and wait for it to warm up. When the engine starts to stumble, pull off the vacuum line. If the EGR is bad, the engine idle will stabilize and no longer stumble.