04 Ls430 - Vibration When Gas Released On Freway

[Will B.]

I've noticed that when I'm driving on the freeway and begin to coast (i.e. let the foot off the accelerator), I notice a vibration in the car. When accelerating even a little it goes away. I thought it was just a tire balance issue, so I got the tires balanced today (cost $80 - yikes!) and it's still there. Any ideas as to what else it could be? I'm taking it back to the dealer on Tuesday - for $80 I want it fixed - but would like to have a general idea as to other possiblities.

Note that I only notice it on the freeway, although it very well could be at any speed 45+mph.

[90LS400Lexus]

I've noticed that when I'm driving on the freeway and begin to coast (i.e. let the foot off the accelerator), I notice a vibration in the car. When accelerating even a little it goes away. I thought it was just a tire balance issue, so I got the tires balanced today (cost $80 - yikes!) and it's still there. Any ideas as to what else it could be? I'm taking it back to the dealer on Tuesday - for $80 I want it fixed - but would like to have a general idea as to other possiblities.

Note that I only notice it on the freeway, although it very well could be at any speed 45+mph.

Hi William. On a 04', which I am sure is smooth as silk, I would imagine that vibration is quite annoying. I was going to say engine or transmission mounts, because that is usually something that causes vibrations on LS's, but since it is only an 04' I would not think these would already be bad, but either the engine mounts or tranny mount may have failed prematurely.

I have a 1991 LS400 with 211K and it has a very annoying vibration, which I am assuming is from worn out engine mounts. I am just not ready to cough up the $530. to let the dealer change them. Unfortunately I am not a very wealthy person I have no idea why I bought another Lexus, knowing I could not afford the upkeep! :(

Hope you get it figured out. Keep us posted and take care!

[chilkoot]

how many miles since your last transmission flush?

[SRK]

The change due to drive-coast in the driveline leads me to think of the driveshaft - perhaps the flexible couplings at either end of it. Although they are very tough and reliable, it could be one of the half-shaft CV joints. And of course the transmission mount might also be a factor. It's not wheel balance - save your money on that one.

[Will B.]

I bought the car certified pre-owned about 2,000 miles ago, so it shouldn't be any fluid issues - vehicle has 45,200 mi now. I guess I'll take it back and let them figure it out. I'll respond if/when they do.