I have a 325is 1994. I heard that on OBD I i can pull codes by pressing a gass pedal or some thing any one knows about this??? please help me with it. my car rmp is jumping when it's just sitting still in neutral rpm jums up and down some times ?? what can this be caused by?? :help

There must be a lot of threads on here about how to do this. Have you tried doing a search?

See e.g.:
http://forums.bimmerforums.com/forum/showthread.php?t=180567&highlight=stomp+method
http://forums.bimmerforums.com/forum/showthread.php?t=233038&highlight=stomp+method