2006 Honda Odyssey shakes around 40 mph

Hi, you could check your engine mounts.

you mean to say the engine is missing?

Hello and welcome to FixYa!

Looks like that you have a bad MAF (mass air flow) sensor. If the MAF is bad you'll have vacuum irregularities. One good reason why your car shakes. Have it replaced and you'll be good.
Hope this helps and thank you for using FixYa! Have a good one!

first get the fluid/filter changed,then get back if no improvement....

It could be as simple as your tire balance is off.

more than likely you need to have your brake rotors resurfaced or replaced

I have this same car with exactly the same problem. Begins shaking at 40mph and stops shaking as soon as you let off the gas, but then begins again as soon as you press on the gas and smooths out as you get over 50. And the shaking is not felt through the steering wheel. Solution: Replace the transmission mounts. There are two of them, one on each side mounted on the frame right next to the shock strut. There is also a front and rear engine mount, but I replaced the two as described and shaking is gone.

low speed shakes indicates a wheel alignment problem
have the suspension and wheel bearings checked out by an accredited suspension shop
under acceleration it could be engine mounts cracked in the rubber being actuated by misfiring form a cylinder
run the fault codes as well

2001 Honda Odyssey 3000cc engine gave me the "shakes". Turns out one of the Ignition Coils failed rendering the spark plug useless. Change with part number 30520-p8e-a01and now runs normally.

if you drive at 40 to 45 dose it shake all the time or dose it go away ?