I have the same noise going on, but on the driver side. I haven't had the chance to seriously take a look at it. I do know my bushings have to look sickly since the truck sat for over a year with out moving and before then they were look pretty worn. I didn't drive to work tonight and just worked from home since I am not to sure what is the true issue. Will try to take a look at it after I go to auto zone and get a code pulled from my lovely ladies pain in the @ss windstar.
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98 5.4 Eddie 4x4 176K (body) med 70k (engine) she's back!
88 Stang 5.0 HO (stock for now)
01 Windstar LX (a huge pain in the you know what
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95 Mazda Protege Dx 1.5L Rotory 5spd 222,252 miles (wrecked - gone but not forgotten)