'98 2200 manual

Was driving home Wednesday and my car died. It lost all power (hp not electrical) and idle dropped to 500, then died. Trying to restart, the engine turns over fine but feels rough, starts but idle doesn't go over 500 and it soon dies (2-3 seconds). I also noticed the theft light came on briefly when cranking/ not starting. Pushed it off the road, called my in-law to pick me up, tried to start it again and it fired right up.

Had the codes read and the Crankshaft Position Sensor code comes up, along with 0440? (gas cap, this one has been on for about two months). Changed the sensor, thought everything was fine, but the same thing happened again today. On the way to town the car died, low idle, rough start, the whole bit above. After messing with the sensor plug, nothing. After trying to start it about 10 time (5 after messing with plug), it fired up. Code read Crank Sensor, emission control. Driving home, died. Tired to start about five times and it started, drove about two miles and it died again. Towed home, tried to start a few times, fired up, now its parked in my garage.

Any ideas what could be wrong? Thanks.