Strange they would not say what the known problem is. Seems there should be a recall if that were the case. I have a 2.3L in my 2001 Ranger and that 2.3 is the new Duratec DOHC 16-valve, should be like yours. I drive it hard, no problems.
'01 Ranger, 2.3L, 5 speed, 83,000 miles. Redline MTL, Amsoil Signature 5w20, Wix Oil Filter, Dynomax Super Turbo muffler.