My car will vibrate while on the freeway (55+). It will vibrate for a few seconds then run smooth for a few seconds and repeat. Any ideas on what might cause this?

 

I moved your thread to the 3G TL forum, but couldn't tell from your post what model car you have, so if you have a 1G or 2G, let us know and your thread will be moved to the proper forum.

 

Sounds like you can reproduce this problem anytime. If so, I would take it to the dealership and have the mechanic or service advisor ride with you so they can experience the problem first hand.

 

I assume it's an automatic - I recently noticed mine (2004 model) doing that too - I think it's torque converter related (since I had the tire problem fixed two years ago when it was new...). Don't notice it at 55mph, but just before shifting, 2nd to 3rd, 3rd to 4th under mild throttle - never had the problem before either, so I am going to take the car to the dealer. It has been a remarkably trouble free car since new.

 

Does the vibration happen at the same speed range? in other words, does the vibration go away at faster or slower speeds? If so, one or more of your wheels may need balancing. If you can feel the shake in your steering wheel, it's probably one of the front wheels.

M

 

Balancing like the others have said
or
If when the tires are cold perhaps flat spotting. In my car flat spotting is post pronounced at about 55 to 60 mph and comes and goes if I speed up or slow down. Once warmed up all is fine.

What tires ? Warm or Cold?

References:
http://www.tirerack.com/images/tires/vibechart.pdf
http://www.tirerack.com/tires/tirete....jsp?techid=42