intermittently over heating

The water pump doesn't go bad intermittently, the thermostat could stick intermittently but you have replaced that.. Air in the cooling system could cause poor heater operation and over heating. Water pump don't go bad on the Acura unless it is the source of a leak. The Acura Tl is pretty good of bleeding the air out once the electric fan has cycled on and off a few times and the system is topped up. The cooling system may have a leak. The way an automotive shop would locate the leak is by removing the radiator cap and attaching an adapter that screws on in place of the radiator cap. Something that looks like a bicycle pump with a pressure gauge attached to it is used to "pump up" pressure to simulate pressure generated when the cooling system is at operating temperature, the leak is then found sometimes it is obviously leaking from a coolant hose or cracked housing, failed gasket or water pump, sometimes the engines cooling system needs to be inspected from below or inspected using a mirror and flash light. A mildly blown head gasket could also cause this.