Vibration Issues and Check Engine Problem

[musicradio78]

Hey fellow enthusiasts.

I bought my 2002 Boxster used in '06. Been an expensive adventure, but I truly love the car. Here's the issue, since day 1 I have had an issue with vibration in the steering wheel. It gets REALLY noticeable above 45mph. I've had it road force balanced several times. I tried different tires. I even had it suggested that the rotors might be warped, but I've had that checked and they are fine. Any thoughts? The dealer, and independent shop, and even a my local mechanic can't diagnose the problem.

Also, check engine light came on about two weeks ago. After having the car in shop for four days, the mechanic still couldn't diagnose the problem - even with the computer code. I had the 60K service, which included replacing the spark plugs (I was told that was maybe the issue). Check engine light came on again. I'm told it may be the coils? Thoughts? Would I have to replace all the coils? I imagine that will spoil the Christmas budget for sure.

Also, can anyone recommend a good Porsche mechanic in Los Angeles. I was going to German Italian Motor Car, but I've been most unhappy with their service.

Regards!

[FrayAdjacent]

Telling us the code that the CEL is generated from would be REALLY helpful.

Saying your check engine light is on with no detail is as good as saying 'something is wrong with my car'.

As for vibration, perhaps there could be a suspension issue or failing tie rods? I'm not sure if the suspension uses a ball joint, but those go bad after a while. I recently had my wheels balanced, and the shop found my front driver's side wheel was bent. Had it fixed, but still have a little vibration. I figure I need to have that wheel re-balanced soon.


Added: I also had a check engine light come on a couple months after I got the car. It was an emissions related code. Cleared it, and it never came back. Have you cleared the code on your car, and has it come back?

See- when something happens once, and never happens again, it's not a problem. The goofy thing about the Check Engine light is, it will STAY on once a code is thrown, even if the situation that caused the code is no longer present.

So first thing I'd do if you have not already cleared the code, is clear it, and see if it comes back.

[RandallNeighbour]

Have a mechanic jack up your front end and spin your wheels to see if he can hear your bearings. If the wheel is hard to turn or grinding is heard, it may well be your wheel bearings.

I had all sorts of body vibration and steering wheel vibration in my car at 60 mph and up... I drove it like a granny on the freeway for five friggin' years, then dropped a pile of money to have all four bearings replaced as well as all the other worn suspension parts on my 97 with 106k on it.

Drives like a brand new car now... actually better (coilovers vs. HD struts/springs).

I guess it all depends on your pain threshold (wallet pain) and how long you plan to keep the car. Had I known that 986's had such weak suspension parts (very soft rubber) and so much friggin' brittle plastic used for other parts, I probably would have saved my money and bought a much, much newer one.

[Cloudsurfer]

Most vibrations, especially speed sensitive ones, are caused by out of round or out of balance rotational assemblies. If those check out, I would search for play in the suspension and steering systems. Since it sounds like you've done the road force balance, ask if they have tried rotating the tire on the wheel to obtain a lower road force reading. This can help. Also, have your tech check the wheels for trueness and runout. As to the suspension, the ball joints in the lower control arms wear and get sloppy. Unfortunately, you must replace the whole arm. Wheel bearings wear, but will typically manifest itself as noise long before causing vibration. Tie rods ends (both inner and outer) can get sloppy and this can cause play in the steering.

Also, make sure you check the rear wheels for trueness and balance and not just the fronts as believe it or not, problems here can manifest themselves up front too. For what it's worth, I know of one member who solved his vibration issue by swapping the front motor mount. A simple test for this would be to at a constant road speed (preferably down a hill) shift the car through different gears to obtain different RPMs, and try simply putting the car in neutral.

Any higher performance car with lower profile tires, especially on larger diameter wheels, becomes VERY sensitive to wheel/tire issues. The entire rotational mass must spin as a balanced and true unit, and this includes the brake rotors themselves.

Patrick