Chasing this cooling issue for months

well hears a thought its still running at 195 blow your tstat if your engin doesnt have the buypass hucked up it cant serculate to give the coolant in the bottem of the block a chance to cycle hence the 175 reading when you go down the road it shut till it gets warmed up at a stop light and opens hope this helps . and do you have your heater on .???