2001 Chrysler Town and Country heat problem

[quote:dc80a1df4c="bradnuse"]Heater problem
2001 Chrysler Town and Country 4 cyl Front Wheel Drive Automatic 112000 miles
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While sitting still the temperature gauge get up to half way and the heater puts out good hot heat. While driving down the road the temperature gauge starts dropping and the heater starts putting out cooler air. I have replaced the raditor cap, thermostat, flushed the system, and the water pump look at. Also replaced the pcm because it was popping up a code saying that it needed replaced. What can I do next to try and fix this problem. Thank you[/quote:dc80a1df4c]
it sounds to me thermostat stuck opening
make sure you have the correct one in by application
also check the coolant flow and the water pump