No heat--What are the causes of luke warm heat at idle & cold air when moving? on 1995 Chevrolet Caprice

car & engine running great. water pump just replaced. coolant flush recent. no engine code. heater valve is new. heater core is NOT leaking.

Asked by for the 1995 Chevrolet Caprice
I agree with wetry it could be a stuck t stat
1 more answer
1- Thermostat stuck open.
2- Heater core restriction.
3- Low coolant level.
That is about it!!