A scan with vagcom would hopefully give you engine fault codes which might help.Common issue could be a faulty temperature sensor but without scan you clutching at straws.Buy yourself a vagcom lead of ebay and using your own pc you can scan your own car.they cost about £10.Best bit of kit you can buy for your car.you could also join us on this forum as yours is the same but different.lol
www,fgoc,co,uk
. instead of , just this site won't let me post www's
Steve
September 2010