My 2006 Tacoma 4x4 4 liter engine that the heater is not warming up.

What is your question?

Please note, the blower is working so our first thought was the Therma Stat but replacing it did not help. It seems to work a little better when the motor speed is increased. We are thinking maybe a vacuum leak on the inner doors or maybe a heater core that is plugging up. Any thoughts?