Are they cranking an engine?
Someone being grouchy?
In the middle of a million definitions that essentially mean the above in http://dictionary.reference.com/browse/crank, i found this: of, pertaining to, or by an unbalanced or overzealous person: a crank phone call; crank mail.
So is there a difference between a Prank Call and a Crank Call? If you are unbalanced, it is a Crank call?
1) do you say prank or crank?
2) do you use both? why or why not?
3) do you use crank only if you are feeling unbalanced or overzealous?