A friend's 92 has had vibration/ buzzing problems (and I've been working on it) for ~ 1 year; and a possible steering problem. He bought it this way. It's mild but annoying. I think there are 3 (possibly) separate problems:

1) A buzz in the shifter that increases with speed and goes almost to nothing at idle; and
2) A slight buzz-vibration you can feel in the steering wheel regardless of engine speed.
3) The steering has resistance and then releases - it's non linear. When parked it takes considerable effort for the wheel to begin to turn. With the wheels in the air there is no initial resistance but there is some as you come close to lock position.

I 1st thought (1) was a poorly done muffler-shop exhaust system - it doesn't touch anything metal but it's twisted some and stressed to one side. And (2) was the usual wheel/ bushing/ whatever.

Recently I drove it and noticed that (1) doesn't vary as much as I thought it did with engine speed; and (2) it is worse. I went to into neutral on a downhill and still felt vibration on the wheel, dash, etc.

I think that the exhaust does buzz a little but I wonder if a road-speed- related vibration has worsened to override it. I suspect u-joints and/ or wheel bearings. The wheel bearings feel fine but I haven't disassembled to inspect the races. And I haven't dropped the driveshaft.

(3) is confusing because of the non-continuous resistance. When I've had this in the past it's been the lower steering u-joint. This one is good (new). I assume there's some kind of valve/ wear problem in the steering rack but I don't know how racks work. I've drained (from the rack) and refilled twice. Old fluid was dark brown. It seems a little better but has the same basic problem. It's possibly just a PS pump delivering low pressure and an inertia problem when starting to turn.

The car has newer tires; they've been rotated; all of the powertrain and suspension bushings are good and many are new. I even put the tires from my car on it - no dif.

The vibration doesn't vary turning
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240s: 2 drivers and some parts cars