17 year old male with blood pressure of 160/78 is that high and what could be the causes .? weight 160lbs.

Yes/hard to say: Yes it is high. It is not run to the ER high but needs to be evaluated & treated if it persists. In many the cause is listed as idiopathic= a fancy word for we don't know. However, there are kidney & other issues that can be reversed if found and that requires some testing. Schedule a visit with your doc. For now, quit eating salty snacks & salting your food.