its not spossed too...you may need to balance your tires
45 mph is the same as 45 mph. How can one of the two be faster?
I should have said that the car seems to sputter at those speeds rather than shake so I don't think it's a tire problem which most people tend to think of.
a = (vf - v0)/Δt 10 mph/s = (45 mph - 20 mph)/Δt Δt = 2.5 s
It is possible that the shaking in a Pontiac Montana at 45 MPH is the result of failing bearings or tie rod ends.
90seconds
problem with your transmission in 5th gear
neither
Tires and/or wheels out of balance?
Wheels are probably out of balance or you may have a bad tire.
No.
24 x 60/45 ie 32 min.