I had bought my wife a ford ranger 1987. At one point it started consuming oil excessively, it was still under warranty so we took it in and they said that if it used a quart in 800 miles that was acceptable. They checked for external leaks, found none. Changed the oil and we drove it home, after ~500 miles the dip stick was at 1 quart low. The problem was the valve stem seals would deteriorate and the oil would go into the cylinder and get burned. They replaced the seal, OK we thought we were good to go NOT. They didn't pull the oil pan and clean the small pieces of seal out of the oil pick up screen so it starved the engine for oil and we ended up having to have it rebuilt on our dime since it was out of warranty.
Lesson>>> do some research as to what Ford Rangers had this problem.
2002 Monaco Windsor 38 PKD
2005 Jeep Grand Cherokee w/5.7 Hemi