The most common problem is cam sensor and drive gear, Ford did that in 95 3L's to present. When the sensor goes out the drive freezes and the oil pump will not turn and starves the engine for oil. They have been known to squeak before the go out, other times they just quit. The mileage does not matter...some have gone out at 100k or 15k.
Other then that the 01 3L's are good engines. Since you will get a 5spd that makes a 3L so much more fun to have. If the Ranger is an edge...you might have 4:10 gears if so you'll be happy with that. My 94 3L is a 2wd, 5spd, 4:10's with 31's and I love it. My 93 3L is a 4wd, 5spd, 4:10's and 31's it seems to drag a little more then my 2wd, but it's all good with the higher rpms. That's another thing like your 4cyl, the 3L's love the high rpms so don't be afraid to take it up when shifting or hwy speeds'.