Hi,I have a 99 F-150 4x4 auto. My heater will not get warm until the truck has been moved. I figured out that if you punch it when you first take off you'll hear a clunk under the dash on the pass. side,then the heat comes on. Each time you shut off the truck you must repeat the process for heat. After it's warm and you shut it off you hear a noise like a swinging door or flap....it's weird. Any ideas? Thanks in Advance

 

That is the blend door, and it sounds like you aren't getting enough vacuum to acutate it.

 

My exhaust manifold has a leak on the pass.side, would that cause it to not have enough vacuum. I was told that's a costly repair and not fun to do, so I've been putting it off as long as I can. It has 161K and runs great(knock wood).