I have a 2015 Mustang Ecoboost (non performance package). I recently changed the springs and suspension with Eibachs Lowering Springs Pro-Kit and Pro Damper Kit. I also added BMR Suspension Toe Rods in the rear and BMR camber bolts in the front. Got the car aligned and it seems fine on the street. The issues i've noticed is at highway speeds. When I am on a rough road (Los Angeles crappy freeway quality), the car's rear end will wiggle a lot from side-to-side and sometimes even have the car jerk to the direction of the un-even road.

I've thought this is maybe the toe rod isn't tighten? or the suspension is stiffer so I just feel it more? Or the wheel hop is coming to play in the car? Not sure where to start or what to even look for, before I go back to the shop and have them try and straighten this out.

Any and all suggestions will be great.

 

Welcome to the forums!




I'd just get it checked out, on two racks, the alignment rack and a regular lift. Wheels supporting suspension check, then wheels 'slack' check and wheel bearings. Just to be sure. But I'm betting that there won't be anything found.

The stiffer springs, lowered suspension, and new dampeners all make for a more responsive, more sensitive suspension that can't soak up and in effect eliminate the wiggle like the stock setup can. Also, if there was all that and you didn't upgrade to higher durometer bushings, the stock bushings have more give, so that's not helping matters. You might look into better bushings for your situation front and back.

And... it could be something else. That's what I got though. Hope that helps!