I had the exact same problem at around 45K too. It turned out that it was a blown strut. I'm kicking myself for having Ford fix it to the tune of $300. Coulda had an entire BAT kit for $600.
1999 Ford Contour SVT #900/2760 (SOLD)
2005 Mazda 6s
2003.5 Mazdaspeed Protege
1998 Ford Ranger 4x4
