MK6 stalling and low revs

Hi,

I've got 05 1.25l which is boggling me and a friend.

So about 2 weeks ago the car got really groggy and a bit slower at reacting but it wasn't giving me any concerns but all of a sudden, if I release the clutch whether the engine is cold or warm boom its stalled and might come back when the clutch is pulled back up but sometimes doesn't. I have replaced all 4 plugs as a test and cleaned the throttle body of the car which had helped sort of, I was getting better revs and car wasn't cutting out but the car would idle at 500rpm once stopped for about 20 seconds then back to 900-1000rpm.

Did some testing on Sunday and if I have the fog lights on and full beams I lose power quicker, but mainly stalls when the heaters are on and demisting the windows.

Any ideas on testing or anyone else suffered this before?

I have looked on Google and people have all said the same things which are mainly IDC and TB. Last ditch is a garage but currently not got asny money for it.