same problem as loads of people get by the sounds of it mate
most likley to be either, map sensor, act sensor or ect sensor.
you can test the act & ect sensors by starting the car and letting it idle, then pull the plug off one of the sensors and bridge the contacts on the plug with somthing metal!
this will make the ecu think your engine is warm cause there is no resistance and cut the fuel back.
if you here the engine get better when you do this you know uve found the fooked sensor.
my moneys on the act sensor!
