Lost 1 quart of oil in about 10 days of driving. It's not leaking out,and there is no visible smoke,but I get a whiff of burning oil from time to time. The idle doesn't sound quite right and oil pressure fluctuating at idle with a slight stumble.Car used no oil first 500mi,now lost a qt in 170mi.

I don't have air so thinking just make sure valves are closed and vac each cylinder,or is there more to it? Tips? Ideas?