Be sure to tell him if that truck EVER starts to overheat, shut it down and turn the heater on high. These engines are notorious for cracked heads, etc.. It doesn't take much to crack one. I've changed around 5 on mine. All cracked. All in the same location.
If I lived somewhere that I didn't need heat, I'd remove the thermostat permanently on mine.
As for your 2.9 being a dog, take the intake hose off and look at the throttle butterfly. Have someone push the gas pedal to the floor and see how far the butterfly opens. If it's not opening all the way, then get under the dash and look at the slack in the throttle cable attached to the pedal. Some zip ties pulled tight around the cable will take up that slack and give you back the ability to achieve WOT. You can't buy the cable anymore.
2001 Ranger Edge Reg Cab 4.0 4x4, Factory 8.8 - 4:10LS -1989 Ranger Reg Cab 2.9 4x4
“The automobile changed our dress, manners, social customs, vacation habits, the shape of our cities, consumer purchasing patterns, common tastes and positions in intercourse”