SmellyCat

What could cause my 04 A4 V6 6 speed to not start once or twice a month? When this happens, I have to push the gas pedal to the floor and crank it for about 10 seconds and it will start. puffs of blue black smoke come out the exhaust after starting this way. Otherwise the engine does not smoke at startup. I do use a quart of oil every 2000 miles. I have about 125,000 miles on the engine. Thanks. SC