if I'm not mistaken, they not using goal difference as the tie-breaker. They using head to head results to separate teams that tied on points.
so a tie with costa rica where we score goals would give us the tiebreaker over them. Of course that wouldn't help us make up the 3 pt deficit. A win at costa rica gives us the tiebreaker and closes the gap at the same time.
we can't beat guatemala in the tie breaker, however Guatemala has probably the hardest remaining schedule (US, Mexico, CR) and we are currently level on points.