1994 dodge caravan heat problems

1994 Dodge Caravan, 3.3, auto, loses heat while driving. Had 160 degree engine, changed stat, got 195 degree engine, same problem, checked heater core, not plugged, changed water pump for more flow, got 180 degree heater core hoses, 145 out vents at idle down to 95 when driving at highway speeds. Any ideas, assuming something in the dash to be wrong. All help is appreciated.

try 220 or use card board cover 1/3 raditor not work check temp gauge