s_m

Hey folks! I love the forum - you have some great content on here.

I have a question regarding a front-end vibration that I am experiencing. Some quick background info:

1) 2006 GS300 - 17,000 miles
2) Vibration first started at about 10,000 miles. The vibration only occurs briefly when I let off of the gas between 70-75 MPH. Vechicle is smooth as glass when I keep gentle pressure on gas at that speed.
3) Replaced original Dunlop's (those tires were terrible) with Michelin Pilot Exalto's at 15,000 miles. Had front end re-aligned and tires road force balanced at time. Vibration would still occur when I let off of the gas between 70-75 MPH. No vibration if I maintained that speed.
4) Had front end re-aligned and tires road force balanced again. Same result.
5) Took vehicle to local Lexus service shop to diagnose. They are claiming it is the tires (feathering/cupping on inside of tires). I can't feel or see what they are talking about.

Does this seem legit? I just find it hard to believe that two uniques sets of tires can show the exact symptoms, especially with the newer Michellin's after driving out of the tire shop.

Any suggestions?

flipside909

You may want to try another Lexus dealer in the area to get a 2nd opinion. There could be a few things that maybe a problem. These are just somet things that quickly come to mind: Front wheels are out of round, brake rotors could be heating up (result of sticking calipers) or worst case scenario, you could have a suspension issue (bent control arm, link or even premature worn shocks).

Since your tires/wheels have been road force balanced, we could probably rule out the wheels out of round but you should ask the service dept for the specs on their balancing.

chocaholic

I had the exact same symptoms with my 06 at about 16k mi. I replaced the original Yoko's with Khumo ASX's and the problem was completely resolved. I had a hard time believing that tires could cause such a noticeable vibration when lifting off the gas at freeway speeds. I know it's unlikely, but perhaps your new set of tires has one with a bad / separated belt. Have you tried rotating them to see if you have the same issue?

3GRFSE

My car is doing this even with the new michelin's.If I had to guess it sounds like a driveline issue.I have been looking to see if a TSB has been issued under NVH.There is also a possibility that this problem cant be resolved,like if its a design flaw that they built into the car without even knowing it.

nardeezy

I doubt it's a driveline problem. Performing road force tests are very technican dependant! The guys with more epertise are more patient and tend to do a much better job. Try taking it to a motorsport shop that specializes in custom alignments and custom wheels.

NAZTY97

I got the same problem... and I am thinkin' I have bad shocks.... I experienced this on another one of my cars... I think when you apply throttle.... it forces the car downward ( pressure between car and ground ),... when you release, the car's wheels are free to bounce uncontrollably and you feel it....

I am thinkin' I am about to get some new shox ( hopefully there will be more than factory OEM's out there ). And I have new tires on too.

noncom23

Also check the wheel balance without the tires mounted. Also check for damaged wheel...