tungo

iTrader: (16)

My service advisor and technician put 60 miles on the odometer to try to diagnose it. They spent nearly the entire morning with the car and and they were able to get the vibration to go away completely at 40-50 miles by adjusting the stiffness of my suspension. My suspension was set at the stiffest setting and set to the middle to around 15 clicks from the softest setting. In addition to this, he tested the car on different roads and took it to mentioned that above 75 mph, the vibration has subsided. From 70-75 mph, it's very apparent that there is a vibration and I can feel it in my foot.

Because it was still there, he asked the technician to completely dis-assemble my passenger suspension. He removed the axle and it checked out fine. Completely took apart the wheel hub assembly on both the front and rear passenger side and that also checked out fine. Toe links, U-joints are also okay. Also took measurements and compared it to the driver side and everything is okay. Everything is tight. He also said that the car is mechanically fine. They believe that it's from my coilovers and the dampening as it is not compensating for such a heavy car. This is a possibility.

I drove the car at the indicated speeds and sure enough, it only vibrates now between 70-75 and still enough for my forearm to have to struggle a bit with the wheel. At this point, I'm convinced that it is a moving part that is off center. Perhaps a carrier bearing, or something with the rear differential. Any ideas?

Spent all this time and came in expecting my service bill to be a few hundred dollars just to look at the car. Instead, got charged only for a loaner for less than ten bucks. He didn't want to charge me, because he couldn't fix the problem completely. Best experience I've ever had with a service advisor. But I could still use some advice on where to go from here.

mmarshall

Two questions from here. First, did the service department check for any factory TSB's (Technical Service Bulletins) on the problem? The F-Sport suspension on the GS is still pretty new, and there could (?) still be a teething problem with it. TSB's are factory-updates to address non-safety-related problems the engineers find after a car has been on sale, or in a pattern of problems that customers themselves report. Satety-related problems, of course, generate recalls, not TSB's.

Second, are you running the tires at the recommended PSI? (the pressure after they have been sitting out of the sun for at least three hours?). If there's too much air in them, they could accentuate any damping problems that an overly-stiff suspension is causing.

tungo

iTrader: (16)

Yes and Yes. All TSB's are up to date.

Tires are run at 35 PSI front and 36 PSI rear. It fluctuates from 35-38 PSI. It's not my wheels or tires. That I am certain. I'm leaning towards potentially drivetrain and or minor frame damage potentially. Suspension is all in tact.

bitkahuna

iTrader: (20)

is it possible one of the coilovers is damaged?