Why is my truck using so much oil so fast?

The check engine light is on

Scan for codes. What oil do you use and how many miles per quart?

I haven't scanned for codes yet but its using a quart about every 300 miles

5w 20 synthetic

My 02 F150 with 220,000 miles uses one quart in 3,000 miles. Check your PCV and try a heavier oil such as 5W30. You may also want to try a engine flush to loosen up stuck oil control rings. How often do you change oil?

I bought it from my uncle a couple of months ago and he babied it but he got a new truck about 6 months ago and parked it. I was just told that it could be the rear main seal. Im gonna check the codes and get under it and check the rear main seal tomorrow. I was told that that seal could have gotten brittle from it sitting up and it would be a high pressure leak that would blow out oil while I'm driving it

If it is the rear main there would be a lot of oil on the undercarriage. Try putting a clean piece of cardboard under the truck and let it idle for several minutes. The oil leak should show up.

Ok. I sure appreciate your help