Just providing an update regarding my vibration issue. I have been waiting since May 11th for something to be done since the new tires did not correct the problem. GM Canada gave me a call on Monday (after I called and left them a message) and told me that they would send out a field engineer to have a look at my car. I was told it would take about a week for that to happen. Well, I received a call yesterday at work from my Dealer asking if I would be able to bring the car in before lunch as the field engineer would be here that afternoon. I was told that it may be ready today but they could be sure and it may take until Monday. Since the field engineer wasn't there when I dropped my car off I have no idea what they intend to do or if they can actually do anything to cure the vibration. At this point I am pretty sure it is an AFM issue. I'll provide an update as soon as I get my car back
I just put a call into my Dealer. The field engineer is recommending replacement of the engine and trany mounts. Of course these aren't stock items so I have to wait until they arrive. My own gut feeling is that they will replace the stock ones with ones that provide more dampening in hopes that the vibration won't be felt as opposed to actually fixing the vibration. Again, I will update when the new mounts are installed.
Just wanted to provide an update as I started this thread back in 2008 and am still enjoying my G8 GT, but with substantially less vibration if any at all in most cases. It all came down to improper wheel balancing over and over and over. To this day, it is still not 100% balanced, but is 99% perfect. I had to take it to several private wheel and tire places as the dealer network just didn't care, or employed people with the less than required skills to do the job right. I don't think the Goodyear Eagle RS-A's are as horrible as I had originally thought, but I am happy to say I am rolling on Kuhmo Ecsta SPT summer tires which made a massive difference in ride and handling as well as getting off the line. Anywho, I am glad to say it has absolutely nothing to do with DOD, TCM, driveshaft, mounts or any other of the potential things it could've been based on the other posts. The only thing that is quite evident, is that tempurature is a huge factor in the vibration or lack thereof, even after waiting for the tires to warm up. (is it possible that the alloy used for the wheels is just extra sensitive to tempurature or that they're just extra sensitve to wind and road vibration?...I have no idea how or why as I am not an expert). Either way, it's all good, the G8 is likely to become a modern day collectible due to Pontiac's demise and the GXP is not coming to Canada which helps with the values as well. I'll update again, thanks to all who've responded as the feedback was helpful.
Just wanted to provide an update as I started this thread back in 2008 and am still enjoying my G8 GT, but with substantially less vibration if any at all in most cases. It all came down to improper wheel balancing over and over and over. To this day, it is still not 100% balanced, but is 99% perfect. I had to take it to several private wheel and tire places as the dealer network just didn't care, or employed people with the less than required skills to do the job right. I don't think the Goodyear Eagle RS-A's are as horrible as I had originally thought, but I am happy to say I am rolling on Kuhmo Ecsta SPT summer tires which made a massive difference in ride and handling as well as getting off the line. Anywho, I am glad to say it has absolutely nothing to do with DOD, TCM, driveshaft, mounts or any other of the potential things it could've been based on the other posts. The only thing that is quite evident, is that tempurature is a huge factor in the vibration or lack thereof, even after waiting for the tires to warm up. (is it possible that the alloy used for the wheels is just extra sensitive to tempurature or that they're just extra sensitve to wind and road vibration?...I have no idea how or why as I am not an expert). Either way, it's all good, the G8 is likely to become a modern day collectible due to Pontiac's demise and the GXP is not coming to Canada which helps with the values as well. I'll update again, thanks to all who've responded as the feedback was helpful.
oops, sorry Mr. Moderator, not sure how I managed to post this twice in the wrong spot, meant to post it at the end of the thread...... sorry guys!!!
Hi all,
Just wanted to provide an update as I started this thread back in 2008 and am still enjoying my G8 GT, but with substantially less vibration if any at all in most cases. It all came down to improper wheel balancing over and over and over. To this day, it is still not 100% balanced, but is 99% perfect. I had to take it to several private wheel and tire places as the dealer network just didn't care, or employed people with the less than required skills to do the job right. I don't think the Goodyear Eagle RS-A's are as horrible as I had originally thought, but I am happy to say I am rolling on Kuhmo Ecsta SPT summer tires which made a massive difference in ride and handling as well as getting off the line. Anywho, I am glad to say it has absolutely nothing to do with DOD, TCM, driveshaft, mounts or any other of the potential things it could've been based on the other posts. The only thing that is quite evident, is that tempurature is a huge factor in the vibration or lack thereof, even after waiting for the tires to warm up. (is it possible that the alloy used for the wheels is just extra sensitive to tempurature or that they're just extra sensitve to wind and road vibration?...I have no idea how or why as I am not an expert). Either way, it's all good, the G8 is likely to become a modern day collectible due to Pontiac's demise and the GXP is not coming to Canada which helps with the values as well. I'll update again, thanks to all who've responded as the feedback was helpful.
Another update! On my last thread I posted that the car was 99% fixed, which was just me getting excited I guess..... it was smooth for a few days, but everything is back shaking and vibrating and has been for months. I brought it to several places, some GM dealers, some private places and nobody has fixed it. The main issue is the lack of service I am getting from my primary dealer, but the car is back with them today and a GM specialist Engineer is working on it. Could it be the Front sway bar bushings? Rims bent? Rotors warped? Lower A-arm has too much play? Just needs an alignment? I don't enjoy the day to day anymore in my G8 as it always shakes, and I can't sell it as the shake is obvious. Just wanted to update and see if anyone has had any luck over the last year getting the vibration issue resolved and what it might have been? They've already replaced a ball joint under warranty which seems to be a problem on almost all G8's, so the clunk went away but still vibrates... HELP!!! Anyone have news or advice? I really want to keep the car. (see previous posts on this thread for the history)
I have owned 2 G8`s this year. Both had issues that were finally solved by changing out the control arms. First car was a 6cyl. the dealer started by turning the rotor`s and re-placing the original tire`s. That smoothed out the ride cosiderably but not perfect. Last they changed the control arm`s in the front, that was the cure.
GM informed me on Nov.13th that they will be changing all (front and rear) control arm`s on my GT. Vibrations start at 55mph and dissappear at 90 mph. I`ve only been able to put on 2000 miles since June 1st because highway speeds were a killer on the fore-arm`s. Makes you want to drive at 100 mph all the time!!
Bottom line is "The General" thinks the issue is in the control arms. Must have documented complaints to have this work done. 2 mth. wait here in Canada for parts I`ll see them in the spring after hibernation! Hope this helps. Go see your dealer for warranty info. releaseas of November.
UPDATE: Vibration remains after a few more attempts by the dealer to fix. SOLD THE CAR, no more G8 GT. Thanks all for the feedback, too bad, was a nice ride otherwise.
A few things could be going on here depending on your situation.
I can tell you to check the tires for cupping. Trust me when I tell you after a bad alignment and 1200.00 on new Goodyear Eagle F1's were ruined. The vibration was from the cupping that occured on the tires only after 200 miles. You can either buy new tires or sell the car.
Another situation occured when the low hum occuring in the cabin at high speeds on my GTO, it was because of bad U Joints and the drive shaft. The dealer replaced the entire rear end, drive shaft and u joints to no avail. The vibration was still there. In the first two situations, I sold the car.
Most people don't get their G8 pedderized and have a 4 wheel alignment performed by an authorized pedder dealer, using special tools that align the front and rear cradle. No Pontiac Dealer carries the special cradle alignment tools that an aftermarket shop uses. I would seriously consider dropping 150 dollars on a cradle alignment at a local authorized pedder dealer. That took care of my vibration for good. And it looks cool too with all the Red bushings.
My vibration originally came from the tires and Pontiac put on new Michelin's that made a big difference in the ride quality. Most of the vibration went away, but now it will change lanes by itself in 4 seconds on the highway. Car now pulls to the right at any speed?
Also, now I have a overall vibration with the cruise control on and the car is running at a steady speed?
I've got a weird subtle thud noise coming from the right rear end when I'm doing 20-40 Mph... I took it to the dealership (since I've only had the car for a month). The tech said he can hear it but he cant figure out where it's coming from. He put some kind of sensor on different parts of the suspension to try and isolate it but he said the car is pretty stiff so the sensor is picking up normal noises associated with driving. They told me to drive it around some more until it is more noticeable and they will try to find it again. He mentioned it sounds like a shock absorber that has gone bad on the inside but the shocks checked out okay...
I have a 2009 g8gt that seems to have the vibration in the fuel mgt system. At no load it feels like the engine is misfiring. Dealer says engineering is working on a fix. Does any one know more? Meach240@aol.com
I had a vibration problem as well and it turned out to be two separate issues. I also got a new set of Michelin tires (way better than the Bridgestone rock tires). The tires covered up the second vibration in my car.
Car just needs to be at a steady speed, but the cruise sets it off for sure. Get to around 70- 75 MPH put the cruise on and wait. Get on flat highway and feel the shifter vibration. The dealer calls this "characteristic vibration" / "harmonics".
I had a vibration problem as well and it turned out to be two separate issues. I also got a new set of Michelin tires (way better than the Bridgestone rock tires). The tires covered up the second vibration in my car.
Car just needs to be at a steady speed, but the cruise sets it off for sure. Get to around 70- 75 MPH put the cruise on and wait. Get on flat highway and feel the shifter vibration. The dealer calls this "characteristic vibration" / "harmonics".
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Vibration Update
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