Car rocking back and fort?

[FNK]

Something in my car, engine mount are fine, feel like it's moving back and forth when I'm accelerating over a rough surface such as road cracks.

It's getting gradually worst over time. What could it be, I have to idea.

[geeky]

Have you checked your rear diff and tranny mounts?

[Seerlah]

You would really need to look over all of your mounts and suspension parts to conclude which one is faulty. Not sure how to diagnose all of them, so you would need an expert to chimme in. We can conclude it isn't your CAs or tie rods. But that does not pertain to your shocks, springs, or sway bars. And it can be something as simple as a loose bolt or a bolt that had become dislodged. As for mounts, you would need an expert to check that out for you or have an expert chimme in on advise on how to diagnose. I know for the motor mounts, you would look for the purple ooze (inside fluid) that leaks out. Your snub mount could also be gone.

There are many variables here to look for. But fixing it should not be costly (free if you can , minus parts). If you know of a reliable shop (reliable, as in not known for ripping people off), shops usually charge around the $85-115 mark for "full diagnosis" (one of my mechanics charges $85, while the other will take his time out and look it over for free if you know for certain where the issue is coming from, as not to take too much of his time). This would include the reason why your vehicle sways. But be sure that you go to a "relibale" shop that works on Euro cars (Porcshe, Mercedes, BMW, VW, Audi, etc). If you post in the Canada regional section, I am sure there is a mechanic on there (on this forum baord) that will help you out. I met my mechanic on Audizine.

Post here

[FNK]

Great reply!

More infos,
Moving the car side to side, #1, no sound.
Braking + Accel/Reverse while stopped, #1, no sound.

Engine mount, a little purple color around them, but might be the old motor mount replace by the previous owner (if replaced), (Took some pic but lost my Usb wire...) never the less, poking in the hole feel like there is an equal amount of "Purple goo" inside. I compared to my two brand new engine mount. The new have more of it, but it could only be because they weren't compressed, thus the geometry inside wasn't the same.
Sway bar Bushing are in place and no play.

My control arm bushing are all cracked, but none are loose or feel loose. They aren't teared either. (Pictures too, I'll post them later when I'll find that darn usb wire).

[Seerlah]

Wow, I would replace my CA if I were you. Go with FCP, and you will get a lifetime warranty (check the fine print). But yeah, having the engine rock excessively will def make the car itself unstable/unbalanced. No expert, just granting my advice.

[FNK]

Wow, I would replace my CA if I were you. Go with FCP, and you will get a lifetime warranty

What do you mean by CA and FCP?

[ECS Tuning-Audi]

CA are = control arms.

FCP = a supplier.

How many miles are on these control arms? Any noise of bumps, like thuds, etc, when you enter driveways?

[Seerlah]

As Chris@ESCTuning stated, CA is an acronym for Control Arm(s) and FCP is a company that sells them (for the best price, but not the best quality. but still, lifetime warranty if a part does fail).

[FNK]

Indeed, over a small bump, it knock somewhere on the front left. After more testing, it feel/sound like it could be coming from around the wheel.

[FNK]

Those of you who changed the control arm set, did you change the bushings alone or the whole control arm set.

I have acces to an industrial press to replace them. Is this the only reason people have to pay 800$ for the kit?

[wikid57]

Don't rule out a possible strut issue either. When you drive over bumps does the car seem to bounce excessively? If unsure, simply drive the car over a speed bump, if the struts are good it shouldn't bounce or "wash" around. This could easily be whats generating thuds and knocks. Also, if it happens to be the control arm bushings, you do not need new control arms(unless they are damaged which typically wouldn't happen unless the car is in an accident or hit a curb etc) you'd only need the new bushings which shouldn't be very expensive but they usually need to be pressed into the control arms.

[stubbs]

The full, 12-piece control arm kit from FCPGroton on eBay (the same company that's been talked about before.) is only $215, so unless you can find bushings for incredibly cheap, they're not worth it. Also, the ball joints on the end of the arms frequently wear out faster than the bushings, and you can't replace those. I'd recommend just replacing all of the control arms. It really makes the front end feel much tighter and more solid after worn ones.