Intermittent Vibration at High Speed

[dbgmpd]

Hello. I have a strong vibration that is intermittent in 5th gear at 65mph+. You can feel the vibration begin from the rear of the car and then it feels like the steering and rear of the car is vibrating/shaking. Lasts between 30 seconds to 1 minute. Usually acceleration/deceleration will make it stop sooner. There is no rhyme or reason for when this is going to happen except at 65 mph+ highway driving. The car has 10 mos old new tires and rims. The car has not been driven much during that time; sometimes not being driven for 20 some days and the car is driven mostly in the city.

[RFM]

I would recheck the wheel balance to start with.

[rp2.5]

My 2.5 as doing about the same but at 72mph. Rechecking the balance is about as easy as it gets.