Don@STaSIS

Howdy! First technical question for you folks. The 90q20v exhibits the strangest vibration I've run into in any car. When driving below 65mph everything is fine, tight, clean. Above 65mph the steering wheel, and whole car, shakes for about 30 seconds, then it stops, then it comes back a minute later, 30 seconds of vibration, then back to smooth travelling. When there is a vibration causing problem I've always found it to be constant, but this vibration cycles in and out on a time schedule.

I've checked every suspension component for tightness, control arm bushings, ball joints, tie rod ends, tie rods, rack, and so forth. Only thing that looks mildly worn are the front strut bearings. Wheels/tires were balanced not too long ago and this vibration has persisted through the snow wheel setup and then back to the summer wheel setup. Only odd wear I found on the snow tires was some weird cupping on the right rear tire, but it came out that that wheel was out of balance, thus the cupping.

Now this cycling vibration above 65mph does not change with accel or decel, does not change with terrain, does not change with gear or engine rpm, vibrates in the same manner up to 120mph, more of an annoyance than anything else.

Does anyone have half a clue to what this may be? On the old 80t I just replaced everything at once, coilovers, shocks, strut mounts, ball joints, tie rod ends, control arm bushings, all rear bushings, and so on. That surely solved the vibration in that car, but also set me back severely.

TIA!

Hokie - STI avant

This also happened on my car. I put my stock wheels/tires back on the car and the problem was fixed. Apparently the tires I had on my other wheels somehow got "out of round" which caused this vibration at higher speeds.

Mike