We bought 2001 Sienna new. At 230,000 replaced shocks. Coincidentally or not the next day we began to experience a violent shaking at 40MPH. Haven’t since. Forgot to mention that engine light went on. We’ve already replaced catalytic converter years ago.
Ask the shop that replaced the shocks to check them out again. It sounds like something may have gone wrong with the installation.
Have the codes for the check engine light read. They might be leading you to the right solution.
I don’t see a question here.
Have the ECU scanned for stored fault coodes. Post them here.