alignment
I don't know what kind of work you've done, but mine was doing the same. after a thousand dollars of work done, it's really starting to drive great. Mine is a 1999 expedition EB 4x4. Here's what I was forced to do after putting new tires on: new shocks all around, steering linkages, all four tie rod ends, pitman arm, control arm?, new brakes all around, new rotors, and wheel hub bearings. I've had it in different shops for 2nd or third advice. Most shops told me everything was tight up front, but this one mom n pop shop narrowed down my problem to wheel hub bearing. just got it done yesterday. Drives great. I know you may be thinking that i should have done all this work before doing the tires, but when i have shops telling me everything's okay, my attention turned to other things. A sound I was hearing was a clunk while turning my wheels and on an incline. Get them checked out, it seemed to be overlooked by most shops.