sounds like some kind of flat spot caused by one of a few things, the power on mine is pretty poor down below 3-3500 rpm then after that its revvy and of it goes but thats the charactiristics of the 20v engine, its got to be revved to get the most out of it, but if you think yours has a prob id take it back to the dealers where you had service and say since the service its not running right, they might fall for it and have a nosey, failing that could be maf senor,temp sensor or other things check on here through all the pages on mk4 section as theres been a few 1.8 20v engine prob threads!!!!
