One problem related to engine rattling and whining sounds has been reported for the 1999 Ford Ranger. The most recently reported issues are listed below.
Took truck into dealer for first oil change and was informed that Ford was replacing the 4. 0 because of rattling noise in lower end. 2nd motor would miss and foul plugs every 2 or 3 thousand miles so they finally replaced it with a 2000 model 4. 0l and this seemed to solve the problem until recently when the very loud rattling noise returned. I've taken it to the local dealer where I live now and he confirmed the noise but Ford won't respond to his enquiry about it. It sounds just like it did with the original motor and now its out of warranty!.