Start with the easy things and work your way down. Leads, plugs, coil, air filter, MAF, leaky hoses , fuel filter, fuel pump and anything else mentioned above. Unfortuantely there's a shed-load of things that this could be. Check everyting related to the fuel / air mixture, and (as stated above), a VAGCOM check wouldn't go amiss. The 'very dirty' intake might be my first port of call. Any crap getting into the engine certainly isn't doing it any favours. Maybe try that injector cleaning stuff also (i'll probably get shot for suggesting that). However, if it's getting progressively worse, it