KX250f won't idle

I have a 2014 KX250f in good shape, starts up with 2 or 3 kicks and runs well when on throttle. The problem is the bike will die very quickly if I don't rev it constantly when clutch in. If I'm in 1st with clutch in it will die without being revved but if I put it in neutral the bike revs super high for a few seconds, drops down, then dies. Only idea is maybe a bad TPS?