OR3X your truck has the V6 engine, right..?

Adding oil to the cylinder when doing compression test might increase the psi and if so (I think) that means piston rings leak..?!? Maybe a valve is not closing properly, hope it's an easy fix and not a blown head gasket or needs cyl head work... Test the coolant for gas that leaks from bad head gasket, O'Reilly's loans free test kits...

You will fix it oorah ;^)