I have an 1996 Audi A4 1.9 TDI SE 110bhp.

The problem I am having is that I feel I am losing power at high revs and there is also a lot of black smoke coming from the exhaust when the power is being lost from the engine.

Has anyone encountered these problems before or have any ideas what could be wrong with the car.

Any help would be greatly appreciated.

 

Black smoke = burning fuel (in your case diesel).
Losing power = could be low compression.
Check the glow plug.

 

check and see if your catalytic convertor is bad. If its not doing its job or the honeycomb inside broke off and is floating around inside, it will choke your engine and higher rpms and it will dog.

I had that happen to one of my cars but not my Audi.