I have an '04 IS300 w/ 65K mi. I'm getting vibrations between 50 and 65 mph.
I think it's most prominent around 55. I have gotten an alignment, new Michelin tires, and the original wheels are not bent. Could it be worn out control arm bushing(s)? Any suggestions are appreciated. Thanks.

J

 

is it during braking?(could be rotors needing to be cut or replaced)
is it during acceleration?
is it when you let off the gas?

 

the same thing happens 2 me... wen i stop it lightly shakes my tires have been balanced. and wen i acclerate and get up to 50ish miles an hour it shakes as well...???

 

the tie rods cud be gone as well ...jack up the car and see if the wheel shakes up and down or left and right ..that will tell u which tie rod inner or outer i had that same problem earlier in the year. when jacked up wheel shudnt move if it does tie rods..good luck

 

What kind of tires are you running? Are you running spec tires and ratings?
Are you on stock wheels? If your not on stock wheels. Put those back on and see if its the same

It could be the wheel bearings going out.

 

my mechanic checked that, but the wheels are nice and tight. but i do have a slightly bent wheel, and warped rotors. so im sure that my issue. good luck figuring out yours though.