jesmes

Hey guys! Ok, I've got an issue with my 91 300zx that no one has been able to find a solution to. I replaced the struts with new coilovers 4-5 months ago, everything was fine, except the mechanic left the car riding too high. So I went back and they lowered the car to the original ride hight that it was at with the struts and now whenever I get on the highway going 60mph+ my steering wheel starts vibrating. The steering wheel has never shook before, only after I took the car back to be lowered with the new coilovers on. It was perfectly fine with the new coilovers and riding too high...but once I lowered it, vibration in the steering wheel started. I've had my car balanced and aligned more times than I can count, at multiple places, and it changes nothing. I've replaced the tires, brake pads and rotors (front rotors have now been replaced twice in a matter of 4 months because one was warped for some unknown reason) and none of this has changed the vibration in the steering wheel. I don't know if it's something with the U-joints or something not sitting right with the suspension when it was lowered or what's going on. I took my wheels off and put the stock wheels back on and there was still vibration in the steering wheel, so I know it's not the wheels/rotors/brakes. Any suggestions?? I've got a new mechanic helping me to try and figure this out, but for the sake of not spending more money, I thought I might post on here and try to see if anyone else has had a similar issue or another thought as to what this might be? The only other thing I've noticed is that when I'm in 4th gear going 60mph+ the vibration is very minimal, but as soon as I put it into 5th gear, the vibration gets worse. Help! Thank you in advance.

Cobalt60

I don't understand why you replaced front rotors twice. Could be related? I've had the same front rotors on mine since '93. Rotor imbalance, caliper issue?

Also curious that is gets worse when shifting into 5th. Transmission/clutch problems or drive shaft out of balance?

Have you tried resetting the ride height to where it was originally?