One problem related to tire valve has been reported for the 1998 Ford Explorer Sport. The most recently reported issues are listed below.
I have had two flat tires as a result of defective valve stems. Bf goodrich radials were installed at sears on my 1998 Explorer Sport in 12/06. The first valve completely deflated my tire 4 or so months ago while sitting overnight in my garage. I assumed I had caused the slice in the valve by driving, but hadn't hit anything. On 11/26/08 at 7:00 p. M. I was driving I-95 s at highway speeds, and noticed unusual driving sensations. After several miles, I figured out it was a tire going down, and took appropriate action--slowing, being acutely aware of traffic, and seeking a safe exit. When I exited into a grocery parking lot, I immediately got out and discovered my rear passenger tire was completely flat, and once again, the valve was sliced. I searched the internet for defective valves after recalling hearing about defective valve stems manufactured in china several months ago. I learned dill air controls products and the NHTSA had issued warnings regarding same after a death of an orlando, FL man. I am returning to sears to have all 4 of my tires inspected for faulty valves.