I’m looking for advice on this issue. I recently bought a 2004 Mustang convertible V6 auto with 180K miles to be my daughter’s first car. The car has a driveability issue. It has a “rumble-strip” like vibration at speeds between 35-55 mph. This is when accelerating or decelerating. If I slip the car in neutral when driving the vibration is gone. Here is what I have done: new plugs, wires, coil. New u-joints. Front end needed a new tie rod end on right side, new transmission filter and fluid (only replacing lost pan fluid). Another thing wrong with the car (possibly related?) is that the ABS & traction control lights are stuck on indicating a system failure with the ABS.
Note that when replacing the ujoints I noted a couple of things:
1- there is SOME amount of play at the transmission tailshaft bushing. It seemed excessive to me, but a local transmission shop told me that if it is not leaking fluid that it is not a problem. I did not gage the movement, but it was close to 1/16".
2 - The other thing I noticed is that the universal joint for the rear yoke was a little bit stiff, meaning that it did not move as easily as I would have thought that it should. This was the case with both the old rear u-joint and the new, This indicates to me that the pinion trunnion ears are not perfectly aligned, but not sure what I should expect.
Anyone have a similar problem solved or recommendations?