Nissan Repair: 2002 Altima SE 2.5 Heat Flow Issue, heater control valve, heater hoses

Question
Calvin, my altima recently began experiencing issues with the heat air flow from my vents. It only heats when I am accelerating. It isnt overheating at this point but I am concerned that this could be something like a water pump. I read some of the other post regarding this and heard of the heater control valve being an option. Aside checking coolant, could a possible radiator flush be a fix? Would that even be pertinent? How would I tell if it was the heater control valve and if it was in good condition, would the water pump or thermostat be first in the replacement list? Thanks for answering these questions. Feel free to ask me any questions to help us narrow down the issue and I will be happy to respond. Thanks for what you are doing here on this site for those not so mechanically inclined.  

Answer
Hi Rob -

Most likely this is an issue with your heater control valve. This is located in line with one of the 2 heater hoses that attach to the heater core. Usually found going into the firewall on the passenger side of the vehicle. It is run by vaccuum from the engine. Perhaps it is binding and only upon acceleration would provide enough vaccuum pressure to operate. Best way is replace the valve.

Definitely not water pump or thermostat, otherwise you would have overheating.

Hope this helps -
aloha
calvin