I've owned my 97' expedition since new and replaced the torque converter last winter. There was a vibration which wasn't there before. My supplier gave me another converter...same problem. It's worst at start-up and accelaration, but never gone. I've had my vehicle checked out by a reputable mechanic shop and they can't explain it. Last month I replaced the O2 sensors with no change. Engine has 150,000km. Anyone run into this problem and has solved it?