Cold air at idle Breake idle hot air

Could it be the blend door Or vacuum leak

175

So, at idle heater cools off... Then upon acceleration it warms back up but engine temperature never changes... Is that what you have? .. Just for the hell of it.. Which engine .. 4.... 6... or 8 cyl?

8 800 rpm or so can do it Two vacuum canisters, ac and one by brake pedal seem to work fine Blend door shaft moves with knob Stays still when Roma increase Don't know what door does

I'm out of ammo on this one... Sorry.