2023 Hyundai Elantra Hybrid

I am the original owner of a 2023 Hyundai Elantra Hybrid Limited. At approximately 114,719 miles, the vehicle began exhibiting intermittent shaking, rumbling, swaying, wobbling, and lateral instability. The condition is most noticeable at highway speeds and after bumps or other road disturbances, although it has also occurred at lower speeds. At times, the vehicle continues swaying after the initial disturbance has passed. Wind or passing vehicles may amplify the movement, but it also occurs without those factors. Both front lower control arms were replaced. Both front struts were later found bent and replaced. The vehicle has undergone multiple inspections, alignments, balancing attempts, adjustments, and road tests without a satisfactory diagnosis or lasting correction. Rear-suspension concerns included uneven appearance, a rear coil spring that appeared incorrectly oriented, and replacement of the rear-driver strut. The vehicle has also been operated with three Goodyear Reliant 91V tires and one Arroyo 94Y XL tire. The dealership documented differences in sidewall construction and measured circumference between the mismatched tire and the other three. The vehicle was returned with unequal tire pressures, which I documented and corrected to the specified cold pressure of 32 PSI. I gave the dealership descriptions of the driving conditions and multiple suggested diagnostic routes and testing options. I authorized extended road testing, including a technician taking the vehicle home. The dealership adjusted steer-ahead and reset the steering-angle system, but returned the vehicle without identifying the cause of the instability. Immediately after pickup and during subsequent driving to work, daycare, and home, the rumble and occasional sway remained, although less severe. On August 17, 2026, at approximately 120,630 miles, the rumble and intermittent sway remained present. I also noticed an intermittent light metallic rattle and possible passenger-side hum