when i reach 40 mph i feel vibration on my seat driver side more
Vibration felt in the car seats are usually caused by out of balance rear wheels.
How old is your pilot, how many miles on it, how many miles on the tires, and have you hit anything that might have caused damage? Pot holes might have misaligned the wheels.
It’s also possibly a driveline vibration. U joints!
Could be a lock-up torque converter problem too. Try driving to 45 mph shifting into neutral and coasting back through 40 mpg to 35 mph. What happens then?
That’s normal, I had two pilots and it deactivates the cylinders the vcm. Some are worst than others.