I have just replaced the thermostat on my car and flushed the cooling syatem while i was at it....all because i am selling it, the new owner ould not have apreciated the old knackered thermostat.
I have put it all back together and refilled it here is how i did that:

1.attach hoses to radiator and heater bleed vales in the frunk and open valves 3 turns or so.
2.put heater up to hot
3. Fill coolant via filler cap(this took forever for some reason it did not fill very quickly) until full
4. check hoses at frunk have same level of coolant in and close valves
5. put filler cap onto first notch and run engine up to temp.
6. Check coolant level hasn't dropped and refill if necesary
7 repeat steps3,-6

Ok so thats what i have done. I went to drive the car home and as i pushed the accelarator i had on/off power and the car bunnyhoped down the road.
if i sat out of gear and reved in to 2k it just hunts up and down!!

I am trying to give the new owner a fully sorted car and i have no clue as how to fix this.....Please help.
If there is anyone near the hitchin/bedford area that could come and have a look there is beer waiting!!

ki