Do the Doo, on Jan 25 2009, 11:20 PM, said:
Amsoil
I switch to that product right after I bought my 03' Yukon. The engine ran smoother and I had a better gas mileage. You change it onec a year or 25000 which ever comes first. Now my Subaru runs on it and I burn less oil in that car where I was adding a pint every month, not it's a pint every 6-8 months. Amsoil also makes filters as well. Change them when you change the oil. 
Not being a dick here but have you pulled the dip stick to see how much oil is in it? I have a 2000 with 188000 on it and i would typically run it 5000 mile on an oil change. A lot of time i would run into the same thing and when i pulled the dip stick it would be down 3+ quarts. Check it out if you haven't. Could need a couple quarts.











