Hi,
I have an Audi 80 2.0E 1994. Occasionally on startup and run, the car will appear to misfire & burn oil. There seems to
be no clue as to when this happens!. If it is in this 'mode' it will stay like it until next time I start the car. If the car has
started okay then it will run okay for the duration. Any ideas?

Describe the smoke, white, black, blue, etc? Do you actually notice any oil consumption on the oil dipstick?

Offramp,

The smoke is blue and there is increased oil consumption.

If you have high mileage (100K+ miles) on your Audi then I would say that it is the valve seals. If enough oil is leaking past the seals it is going to accumulate on the valve stem and coke (harden) this could lead to valve/s not fully closing. The oil could also accumulate and coke on the rings causing them to seize further increasing oil consumption as well as lost compression. Burning oil also causes the spark plugs to foul until the oil burns off. Do a compression check to get some idea what you are up against.