Seat Leon Throttle Body Problems

when my car is ticking over it seems to be hunting the rev counter flutters

When I am at lights or just sitting in traffic my engine is hunting from 800revs to 1200revs, I have changed the mass metre and oxygen sensor but it did not fix the problem anyone help.

Hard start and limp mode at 3000 but accelerates like a train in between ...when I bought it I was told it had it had a stage one remap