Heater problem

When my car idles the heater blows cold air but as soon as i throtle it up or drive off it starts blowing warm air, just bought the car the only thing ive checked so far is the coolant level wich is fine.

Possibly your waterpump since its impellar is the only thing that would speed up and circulate more water as you accelerate the engine.

I'd check your hoses, water pump and heater core. If it's all original I'd just replace everything anyway, it's old as heck.