[Vwdiesel] Big Problems with Engine (I think)

[Jason and Lori Stoffer]

Hello all, 
 
Every time a post a problem with my 80 vw rabbit pickup you always come through!  Here's another one-  Driving down the road only half mile from the house and then total loss of power with some smoke (?), maybe a bang (?).  Pulled over and the oil cap was off, laying on top of the engine.  Replaced oil cap, checked oil and tried to start engine fires and runs for about 3-4 seconds then dies.  It will continue to fire and run for 3-4 seconds but I don't want to destroy it so haven't touched it since.  Not very fun. Any help would be greatly appreciated.  
 
Thanks,
Jason