what causes the engine light to come on?
Same question, different wording. See your other post: http://community.cartalk.com/posts/list/1902009.page
Some light, some not!
Cast iron engine=heavy
Seriously, however, it is not necessary to post the same question twice. Refer to your other post for responses.
If you are asking "could I be missing something important if I ignore the “check engine light” the answer is yes.