When I start my truck it makes a sound that is almost a sound like an exhaust leak. If I bring the rpms up then the sound goes away. It also goes away after the motor warms up. About 10 mins. After warming up and driving it makes the sound as it goes back to an idle at a stop sign then stops at an idle. The temp goes up fast but remains about normal although the heater does not blow very warm air.

 

Check to make sure your PAIR hose hasn't parted somewhere along the way:
http://personal.utulsa.edu/~nathan-b...78pulsedse.pdf

 

Can you make a video of the sound?