My car takes a while to warm up and when it does it takes a lot longer to get some real heat coming from the heater, it blows warm but not hot. I'm thinking the thermostat might be sticking or I gotta flush out the heater core, any suggestions?

 

Is you heater core valve all the way open? The valve is controlled by a motor that can burn out,Or get stuck in any position..The valve is located on the left side of the car beside your gas peadle behind some black plastic..I disconnected the lever from the motor,It's kind of ghetto but I have heat when I want it..You can reach into the area the valve is while sitting in the drivers seat so as to open and close the heater core valve.Who knows I could be wrong with your problem but it worked for mine