[dwight.j.carter]

It has to do with the rings as they get dirtier. The Northstar is notorious for oil burning it is normal. But there are things you can do to avoid it.
1. Give your car some wide open throttle runs to clear the carbon buildup off the rings.
2. Take it to your mechanic and have them clean out the upper engine. (Not the fun way and it costs money)
3. CHANGE YOUR OIL MORE OFTEN. The sensor is for normal driving and on the gm website it says if you are in alot of stop and go driving you should still change your oil every 3000 miles or in dusty conditions.