16 yr old asked to leave after heated argument she came back later to get her things police wont look for her due to prior runaways can i go to jail for not going after her she has been gone 2 weeks?

No, or the police would have taken you into custody already. She's what they call a "compulsive runaway" and even if she is a minor in your State the police don't have the time to keep running after runaways. If you are simply worried about her then try the old haunts you both hung out at. She is more than likely staying with a friend so you can either go to their place or phone. They may or may not tell you whether she is there or not. This gal sounds street wise and needs a place to flop, so I wouldn't beat yourself up too much.