Oil

One problem is the car manufacturers are saying that it is normal for an engine to burn off 1 quart of oil per 1000 miles. This is due to engineers designing engines to get the required gas mileage standards put on the manufacture, as new cars come out each year. About the only thing you can do to slow up the oil burning is to run a 10w 30 conventional oil in the engine. Manufactures recommend a 5w30 synthetic oil which may be too thin for a higher engine if it is starting to burn oil. The rattle just may be in the exhaust system, a heat shield or something.

I have a 2006 Nissan Xterra with 126 miles on it and the oil is burning in it and the oil gauge keeps dropping too low and then it'll bounce around and I changed everything on it thank you trying to figure out what it is and not sure what it is anyone have any ideas