EVAP Problems?

My wife owns a 2000 Durango with a 318 V-8, 2 WD, we just started getting a check engine light. We had been having a problem with the battery, so we replaced it, and also replaced the battery connectors at the same time. The truck will run fine for a while, then when you go to start it, the battery is drained. Also we are getting a P0443 EVAP emission control sys purge valve code. The truck runs fine if you disconnect the battery, next time you start it the CEL comes on, the next time it starts then dies right away. The latest gremlin is you can turn the ignition to the off position remove the key and "CHRISTINE" stays running.

Starting to remind me of the car from Stephen King's "Christine" hence the D's new name.

Any help is greatly appreciated.