The heater on my feicia is playing up. It only gets hot when I'm at a stand still revving up but as soon as I let off the revs it cools down. What could this be?

Could be the thermostat, the first time I bought my felicia, the cabin temp was never getting hot, then swapped the thermostat over and it was toasty inside once again

I was thinking that too, particularly if you have a slow warm-up.

Pretty sure as mentioned its the thermostat. In my old car i removed it and it always ran a bit cold.. this also makes it drink more fuel so replacing the thermostat would help in 2 ways

Cheers guys thanks for your replys I'm now going to try them out. Danny.