well basically its controlled on the metering head by the 2 black boxes on the side of the meter, mine was doing this and i changed my metring head and no diffence, my coolant temperature sensor wasnt being read by the ecu so was really hard to start and ran like poo not fueling properly, i have seen the black ecu's go on ebay for 10 quid so its worth a try but make sure you get one for a series 2 as series one are different and wont fuel properly under boost! not good, check the color of the sticker on the front (will probably be green) and get the same one, series one have blue stickers, lmk how you get on,