99 Sienna Feels Like Driving on a washboard

[dwagner825]

Ok guys here's the lowdown. Wife's 99 Sienna XLE with only 52 K miles on it. Feels like driving on a washboard at different highway speeds. Does not feel like a vehicle does when the wheels are out of balance. More of an up and down type movement. I felt it twice while on a hard acceleration. Tires have recently been balanced and are all less than a year old. Rear shocks replaced about 2k Miles ago. Any help or suggestions are appreciated.

Dan

[lelandstanford]

Check tires for cupping.

[loytotoy]

I just went through something similar at 68k. I took it to a wheel and break specialty shop. Found out I had 2 bad GY Allegras (which I thought I really liked), turned the rotors (no new pads), readjusted the brakes, rechecked balance. They put on 2 Michelin Symmetrys. It cost about $315 and well worth it.
Buddy, you need to go to a trusted shop that can competantly address balance, alignment, and vibration issues.You need a shop that will fix the whole problem. There is a time to let the pros handle it. That was about the most appropriate call I ever made with any vehicle; without a breakdown first of course. They fixed my ride.