Just got my GTI back from the garage after having alot of work done and i still have the same issue when the car is cold, basically its really hesitant around 1500-2000 revs in every gear until it warms up and i think the previous owner sold the car due to this, parts replaced so far are
Distributor cap and rota arm
plugs
leads
ecu
timing belt replaced and timing checked.
What else could it be as its driving me mad?

The car takes a long time to warm up from cold so could it be the thermostat??
Ive spent a small fortune on the car and it still needs a clutch, having that fitted on Saturday.
Any help would be greatly appreciated.
Cheers, lee.