Hello Everyone,

Okay so I will be taking my 06 Gt in on monday for what feels like out of balance tires. The vibration is very subtle but enough to know that it is there.
However, last night I noticed something. On the highway doing 100KM HR steady the vibration is noticable but very lightly, but if I a crusing steady at 100KM and press the gas down just enough to increase my speed without downshifting into 3rd I can feel the vibration incread steadily unitl I hit 115 - 120KMs. So here is my question: could the source of this vibration be something other than the wheels? Also, if it was something other than the wheels (i,e dirveline, motormounts etc..) shouldn't it be preset at any speed? The car rides absolutely smooth at lower speeds. Starts vibrating at 80KM hr.

Any Ideas?

Hi there; I have the exact same problem with my 05GT, I've been to the dealer so many times and they do agree the car vibrates at 100 kms +. According to the dealer, the tires (Conti's 17") were the problem. They changed 2 of them that were slightly out of specs, but vibration persist. My dealer agree the car doesn't perform like it should, but there is nothing more they can do. I recently bought some winter tires (Blizzak LM22) hoping the vibation would go away but it still vibrates. I've tried to get help from GM and I was told this vibration is a "caracteristic" of the G6??? I do mostly highway travel and this vibation happens in my speed zone. I'm quite fed up with this problem. Could it be the rims? I'm still using my stock rims with my winter tires.

I know there was a recall for a harmonic balancer not being torqued to the right spec, or something like that. I don't know for sure, but it could be causing a vibration. Do a search, I know there's a link somewhere for you to put your VIN in to see if your vehicle has a recall. Hope that helps!

I just received my recall notice for the harmonic balancer (#05548) in the mail this morning. Already made my appointment for early next week. I have a 05GT and haven’t experienced the problem you are describing so I'm not sure if this recall is related.

If you want to see if your car is part of the recall, visit this site: http://www.alldata.com/tsb/General-Motors/1122966000000_1124348400000_05548B/801.html
If you click the Next page link at the top you will see a list of affected VINs.

Hope this helps!