couple of minutes and the car will then crank, start and immediately stall - crank position sensor?

Since I purchased the car 2 years ago, the car has just died while driving down the road or will not start in the morning. No codes are showing up. I have had the O2 sensor, , fuel pump, the wire ends for the starter, and battery replaced. Occasionally, the car will "hiccup" (RPM's drop to 0 the go back to normal) driving down the road. Within a week after a hiccup, the car will just die while driving. The car has died at highway speeds and slow speeds, hot & cold days. When the car dies it just dies-it's like the key was just shut off. When I try to restart, the car will usually not crank. I wait for a couple of minutes and the car will then crank, start and immediately stall. I wait a few more minutes and the car will crank and start. We have had 4 dealerships look at the car, but no one has been able to find the problem for sure. Every time something is replaced, they say the problem should be fixed. Lately, the problem has been happening on a regular basis.