97 Voyager. Stalling issues

I have a 97 Plymouth Voyager and its been running very badly. It will have good days and bad days but still, its kinda scary to drive it.
It kind of idles hard and almost everytime I come to a stop, it will shake, and then stall out especially if I have the air or radio on. When it does stall out, it will take several times to restart, and then I have to rev it a few times just to make sure its not gonna stall out again.
It happens at other times when the vehicle is not stopped. Occasionally when Im making turns or just slowing down in general. I tried having it diagnosed at AutoZone with the computer thing they have, but the lady working there only gave me a code that starts with a P and expected me to figure out what it meant.
If anyone could help, it would be greatly appreciated.