2litre 16v lagging problem!! pls help

[funky]

iv been having problem with my 2litre 16v golf gti mark3... it seems once its warmed up (after about 25mins) it lags and seems like its either missing or not getting the fuel it needs. i replaced the leads and plugs and at 1st it ran worse but now its the same..

when i took the plugs out they were extremely sotted up.people say its a sensor but i thought id ask the people who may no more pls help

Si Mcfunky

[oggy]

If plugs are black soot then you are running rich. Maybe injection system needs sorting or possibly some control sensor somewhere.  If plugs are covered in oil then likely your valve stem seals are shot or possibly even your piston rings or oil scraper gone.

[Pete Taylor]

That'll be the ECU coolant temp sensor broken then. 2 pin white plug one you need from VW. THink they're about £26