I pull the key out and it still runs...

as stated in the title when i turn off and pull the key out my 97 sport it still sputters and runs for a few seconds then dies. it only does it randomly not every time but has been getting worse. Also i was wondering if this problem could be leaving something still on and draining my battery because i have had a completely dead battery the next time i go to start it
Anybody have this problem or know what it is?, thanks

Just a wild guess, but I'd pull the ASD relay and see what happens. It may be sticking shut. Next best guess, would be somebody did some creative wiring and wired something into the wrong circuit and/or is trying to ground something into a key on hot circuit.
The dead battery and the running after shutting it off, suggests a circuit problem, likely the ASD circuit.
Seperately, batteries and alternators fail, carbon buildup inside the motor can cause it to diesel (run after shutting the motor off).