I have poor to no heat in my truck I had heater core and radiator flushed

He said it stays around 200.

SO? Explain it another way!

Gauge could be wrong

Exactly!

at stop light at idle I get heat if I am driving 55 down the road it is cool air

Heater box problem, vented outside air mixing with heated air! Only other explaination.

That's what we're talking about.

how can get to it from the out side

Dont see that post, maybe i missed it. Dont you have a vent setting???

I was talking about thermostat.

they side air box from out side were do I look and how do I get to it from out side to Professor G I tested t-stat by putting in boiling water

It needs to open and close while maintaining constant temp regulated. It still think the heater core is not getting good coolant flow. When it's warmer outside temp it will probably feel warmer in the cab but when the temp is colder it takes higher heat to warm the colder air. Same as sitting still verses driving down the road and forcing a higher volume of air. The core is not getting hot enough.

i am not sure i understand even if it is -6 or 30 deg if i am seating still i have warm or hot heat if i am going down the road it gets cold.

I suppose at this point it needs to be seen by some who knows heater systems so they might be able to test it for you. If I had it here at the shop I could test it for myself and find your problem. Apparently your not understanding is not helping you find this issue.

top radiator hose is hot heater hose on driver side is hotter then hose on passenger side o I forgot to menschen that when I am at running temp and siting still I have heat when I am driving down the road it is cool

May I ask what temperature thermostat did you install? Either the thermostat is staying open while driving, allowing the coolant to cool when driving, or the heater core is restricted not allowing enough coolant to flow through it, or last but not least, the water pump impeller is not moving the water good enough to keep the coolant flowing through the heater core and the cold air going through the core is cooling the core faster then the heater can warm the cold air.

sorry I put a 195

That should be good. Does your temp gauge stay around 200 deg or go lower while driving.

1 it dose no mater what setting am on it is hot when i am seating and cool when going down the road. 2 i do not have a switch or button for a fresh or re-circulate air. 3 yes my truck has ac

blend door or fresh/recirculate door problem.If you're not familiar with heater controls inside vehicle, find someone (shop?) that is.