Why does my car keep dying?

I have a plymouth neon 1996. I have replaced the gasket seals, battery terminal (negative side), spark plugs, computer, pcv tube. After all of this my car is still dying randomly. I can be driving along and all of the sudden my car just dies. I lose the power steering. Headlights stay on along with radio. The check engine light, oil light, and battery light come on. Then the check engine light and battery go away and the oil light remains. I have to put the car in park and start it back up. This only happens randomly through out the day. Normally when I am going slow but have had it happen going 40 mph. HELP what is going on.