hi,hopefully someone can help or give me advice.i have 2003 fabia 1.9 sdi.the engine seems to judder badly at about 1100 revs in any gear,as if its fuel starved.i changed the heater plugs and fuel filter last week,but still the same problem.does it have an maf sensor that could be causing this,or perhaps one of the other sensors.also the fuel economy is not as good as it was.any help please........

unplug it and see if it remains the same. If so its shot

My sdi does same, I presumed it was characteristic of engine.