2005 chevy impala, replaced the idle positioning sensor, now the car dies when it idles, the door alarm doesn't sound when the door is open & the radio stays on even after taking the keys out of the ignition. What??

Thoughts:

. If you have around 125,000 miles on the car, the Ignition Control Module (ICM) may be failing. That could explain the engine dying at idle.

. Check the ignition switch for wear, pitting, or melting.

. Check the door switch.