I am having trouble in adjusting the room temperature. My normal room temperature (desire to be) is 74 downstairs and 73 on upstairs. But couple hours after temperature rise up to 90 on upstairs. The intake is on upstairs, vents are clean and looks adjusted properly.

I have bought new thermostats and they may be working properly. Any suggestion.

This depends what type of heating system you have; forced hot air, gravity, water heat, electric baseboard, or radiant. In either case zoning is the solution, by partially shutting or closing off heat to different rooms. Remember heat rises and forced hot air requires good air flow including cold air returns. I have seen rooms with multiple registers using forced air and remain cold because of the absence of cold air returns. After you let us know the type of system you have, a better answer can be given.

Thank you for your info. Sorry for being late in my part. What I found to have is the hot forced air. I have made some adjutments on the vent air flows but still the temperature on upstairs 90's while other rooms on down stairs are 70's. It seems that the warmer area in the whole house is where the intakes are.

Let me know if any suggestions,

Try closing off all the heat registers upstairs, see what happens.