[caddycruiser]

My G6 just passed 700 miles and in addition to a typically rough or misfire like idle a lot of the time, there's also varied shaking as I accelerate from a stop at times and pretty much all the time at 40+ cruising on glass smooth roads.

The idle thing may be common (weird...but seems that way from forums), but as the rest of the shaking has gone away on one or two random days, I'm not sold on it being tires.

It's going in tomorrow but like with a sunroof rattle I had, it helps to give have some background. Anyone know what this TSB describes?

Service Bulletin Number : PIP4363
Component : ENGINE AND ENGINE COOLING:ENGINE
Summary : ROUGH ENGINE IDLE, MISFIRE (DTC P0300) OR NOISE FROM ENGINE COMPARTMENT. *NJ

I'm trying to research before hand. It's the VVT 3.5L and with so few miles, still something isn't right and isn't getting better. No CEL or anything, just the rumble and wobble, that can vary.

 

[caddycruiser]

Anyone with TSB access or G6 wiggle/wobble/shake experience?

 

[caddycruiser]

Aside from my typical idle studder that I still had checked out to be sure--they said it's normal, which I expected--my other issue has been a wobble while cruising on glass smooth roads--especially at 40 and above--and often the same thing just from a stop as accelerating. This is with the upgraded 18" GY Eagle LS-2 tires.

Described that today at the dealer and let them go at it. Idle, normal. Wobble? There was way too much air in the tires--I did it, and disagree, putting them to 34-35 vs. the squashed looking and soft 30--and balancing one (I believe) of the wheels. I played with the air pressure before to no effect on the wobble just more stiffness in general with higher, but they reset them lower and sent me off after driving it 12 miles themselves.

The first 2 times I drove it a mile or two back to the office and then out to grab something, it did seem smoothed. Then I left for home tonight and accelerated a bit more briskly than usual onto the highway and felt the exact same wobble as before the whole way home, along with more squish because of the lower pressure. Baffled why it seemed to re-appear, but it did--or maybe it never left.

Like a light jiggle I can feel in the seat and car in general, I think from the front. I'm still wondering if it's the tires at all because of the shake while under power, but them balancing and road testing seemed like an answer.

Oh well. Just barely crossed 750 miles Common as rattles and vibrations may be to the G6, the 2 I drove were perfect, a co-worker's '08 GXP coupe has zero vibes after 5k, and mom's '08 Malibu on the same guts is dead steady and smooth. Drives me nuts but I'm hoping another round may be the answer, as with my sunroof noise.

 

[RoGuE]

This may be a stretch and I don't know much about engines but, is it possible the engine could be shaking a lot causing this, since it is under power. Maybe an engine mount or something.

 

[caddycruiser]

This may be a stretch and I don't know much about engines but, is it possible the engine could be shaking a lot causing this, since it is under power. Maybe an engine mount or something.

Possible. Particularly since it did seem to be smoothed until I accelerated moderately aggressively out of work, then wiggle-wobble.

The G6 certainly seems prone to such jiggles, but that said, this one also seemed a bit odd. Lowering the tire pressures to squish level probably didn't seem to help much, other than making it a smoother ride.

 

[scooter10572]

the pi your referring to involves a loose rocker arm with a missing ball or tip causing a misfire,although if a misfire is severe enough the mil will be on,I have not personally ran into this concern so I have no other input

 

[caddycruiser]

the pi your referring to involves a loose rocker arm with a missing ball or tip causing a misfire,although if a misfire is severe enough the mil will be on,I have not personally ran into this concern so I have no other input

Ah...that doesn't sound like this, then. You never know, but still.

Now to get this wiggle wobble straightened out. More and more I think it's drivetrain and not just a tire, but can't narrow it down myself.

 

[newdude]

Ah...that doesn't sound like this, then. You never know, but still.

Now to get this wiggle wobble straightened out. More and more I think it's drivetrain and not just a tire, but can't narrow it down myself.

Not toatally sure, but have you had the CV shafts checked out yet?? onder:

 

[caddycruiser]

the pi your referring to involves a loose rocker arm with a missing ball or tip causing a misfire,although if a misfire is severe enough the mil will be on,I have not personally ran into this concern so I have no other input

I've reconsidered. Especially again as I noticed today, mine isn't just a light up & down or thrumming feel, but more of a fairly hard rumble as it sits there. Then with the shaking as I accelerate and cruise, it makes me wonder more, it's the same kind of feeling as driving with a bad miss, or trying to. But no lights or anything. I don't know anymore. This car was only built in April, so it's not even and old build.

Overall, after they let air out of the tires yesterday and re-balanced one or more, it is getting so bad I can't stand it. Today driving home from work it just shook like I was rolling on logs from a stop and cruising at a very low RPM and steady 45-55, it was a constant and harsh wobble that felt like riding in an old car with a miss and bent wheels. The other thing is the more harsh wobble and shake if you let off the gas from cruising speed...drops the RPM's instantly and feels like the TC or something is trying to grab the car to a stop, unnecessarily.

I didn't call them back today because I wanted to drive it more to be sure, but it's so bad, it has to go back. I've been in 4 different '08 coupes now and none except for mine feel anything like this. And I just hit 820 miles...love it, but I'm not going to put up with violent wobbling and an idle that thumps just a little much.

Oy, I hope we can clear this up.

 

[caddycruiser]

Not toatally sure, but have you had the CV shafts checked out yet?? onder:

No. After only 3 weeks and 800 miles total since birth, I can't fathom what is going on. They thought they fixed it yesterday--and driving 12 miles apparently so--but it's shaking so much now and that idle shake seems a bit too much, that it's driving me bonkers. Not nice to drive as is, whatever the heck is going on.

This needs fixed soon. Vibes can be hard to trace but this one (or these ones) is overtly obvious in a very bad way. Didn't feel like this on day one, but is only getting worse every day, after my only glass smooth road commute back and forth.

 

[newdude]

does it shake/wiggle in park at idle?? or does it do it in gear??

 

[caddycruiser]

does it shake/wiggle in park at idle?? or does it do it in gear??

The idle studder is irregardless of gear, as it does it the same in Park as it does in Drive or even Neutral. Various forums of G6's and even the Aura with the same 3.5L all talk about this and it being normal--as did my dealer, though I don't think it was doing much at the time they had it--I just wonder to what level of normal.

Otherwise, the wobble driving is the feeling of either having something terribly out of balance and or maybe also a studder in the drivetrain. Once up to speed it's the same side to side and up and down waddle along regardless of being on the gas or coasting, though I think a bit more while on the gas. Not a good feeling and I was tired of driving after my 20 minute jaunt. Their first assumption was the tires (as it usually is) and I swear it was smoothed when I left. But accelerate out of work at the end of the day and...waddle waddle waddle again.

 

[scooter10572]

why dont you take it back and see if the tech can go with you and experience the concern,im a tech myself and alot of times info gets lost in translation from customer to writer.sometimes I go directly to the customer and get the whole story,noises and vibrations or rattles can sometimes be difficult to diagnose especially if you dont get correct info from writer.

 

[caddycruiser]

why dont you take it back and see if the tech can go with you and experience the concern,im a tech myself and alot of times info gets lost in translation from customer to writer.sometimes I go directly to the customer and get the whole story,noises and vibrations or rattles can sometimes be difficult to diagnose especially if you dont get correct info from writer.

Yes. Went back again on Monday and was supposed to take a tech for a ride then, but they did a surprise shuffle of service departments and were maxxed out to say the least. What didn't help is, somehow, over the weekend it smoothed itself out to have really only a slight bit of a vibe, and that was still the same on Monday.

I still took it in, as there were other issues too, and told them to re-check. Got a call an hour later and they told me--though now thinking I'm nuts--that they drove it 20 miles (sure did...I looked at my gas gauge) and fixed the one thing (gas cap message) but said they felt and heard nothing. Though, to further it, sternly told me again "You MUST NOT put anymore than 30 psi in those tires." I never did, only put them back up to 31 after they dropped them into the 20's the time before, and that has had nothing to do with it other than it wobbling worse with their preferred flat tires.

I like the guys and they try, but something is still really amiss. After that and it being smooth on Monday still, it started back again yesterday and really much so today, until it was an uncomfortable wobble all the way home that anyone would notice. I'm doubting more and more it being anything tire related, as it wouldn't just disappear for 2 days, but just shakes so much it's worrying. Well, and for just now 1003 miles, I should be smiling and not have 5 service receipts.

Engine, transmission, wheels and tires, not sure, but no car--especially not a new one--should be shaking like this. I'm hoping it will continue to enough of an extent for at least the next day I can stop in and grab a tech. At least to soothe the idea that I'm being a nutty new car owner.

That TSB involving a misfire and rocker arms, etc. still also has me worried...especially after my brother commented tonight that it's the exact same shake in the same conditions his old Regal with valve problems has on the road and at idle. Great. But still no CEL and it generally runs fine, so maybe tires...baffled. Don't know.

 

[CadiEldo67]

When I start my Grand Prix 3.8, I notice a slight vibration while idling, almost like its only in one cylinder, but I don't really think its anything. But when I go 60-70 mph, the front passenger tire seems to make the car vibrate, so it could be a flat spot on your tire, or perhaps something wasn't connected right with the suspension. Nobody needs these kinds of annoyances on a car with 1000 miles on it. Oh, and if it makes you feel better, I just paid the GP off last week, and left the sunroof opened, and it poured, and the inside was soaked. Then I drove through a pretty bad hailstorm, cracked windshield, and slightly cracked turn signal lights, so I'm pretty much at a loss for words. So in a sense, I know how you feel, but its different.

 

[caddycruiser]

Hah! It definitely could and may still be tires, even with the on again off again weirdness (though it's mostly on...always). I drive it 30 miles a day and it only sits overnight, so the flat spotting would be rare, but I know that feel well from several lot car test drives.

So far, 3 other 2008 G6 coupes, and none have had a single shake like mine. I love it to pieces and bought it for such reasons, just driving me nuts. And embarrassing, such as at work. "Where's your car again?" Getting fixed...again.

The service guys were great and worked their arses off, sitting on the phone with the GM tech center for hours as well, to figure out my sunroof rattle, but this shake thing is iffy. It'd also be nice if they didn't assume, just because there's even 1 more psi than 30 in the tires that THAT is the cause...and I just think a firm ride is my issue. Not. But just not right, really not right.

 

[CadiEldo67]

What about the possibility of a bent rim, although that wouldn't explain why you have a shaking at idle. See if you can get a video of it or something.

 

[caddycruiser]

The idle thing is normal, as it seems everyone with one has it, it's just how it idles. Not really a shake but more of a light studder feel.

That said, today was weird. Driving to work in the morning, shake city. Just jiggled the whole way. Went out a couple hours later for coffee, smooth. Later for lunch, smooth again. Coming home, still smooth with the typical lighter judder. There's times on the road I feel it more than others, such as in sweeping arcs in the road which does make it feel like a wheel thing. But I don't know. I was planning on going in today to take a tech for a ride after the way it felt going to work again, but then when it smoothed out mostly, didn't.

Weird, oh weird. Smooth, of course, means still a jiggle but not nearly what it is sometimes. But when it comes and goes like it did today...it's really a WTF moment, and eliminates being able to show them.

 

[caddycruiser]

Freakishly, this morning it was the smoothest it has ever been with NO shake whatsoever. Just a smooth rolling ride and flawless engine response. Not even any rattles.

It stayed mostly like this for the day, then had the typical shaking acceleration and wobble on the road it gets too often. I was going to call and make my return appointment but need to find time and worry the time I go will be a "smooth time" again.

Any idea WTF could have it smooth as glass in every way randomly (like it should be) then after sitting again for a few hours or the day, it shakes accelerating and wobbles like on bent wheels? So bizarre, well, it's just bizarre. If something was really bent or not right you think it would ALWAYS do it, not just 75-80%. Weird, oh weird. You know it really is when I HOPE and cross my fingers it shakes and does so all day so I can get it to the service department and grab someone.

 

[caddycruiser]

As I've known too, and like someone on a Saturn Aura forum said, they had a similar issue where it would shake and then at times be mostly smooth. Turned out to be a bad tire with an issue that seemed to present itself with the right temperature due to a defect, but took a trip to a Road Force balancer to see.

I've thought of just getting it to one, even outside of warranty, but in looking them up (Hunter machines), my dealer is actually listed as having one. Never have seen or heard about such a thing, or what they used to "balance" one before, but I need to ask.

It's definitely something that comes and goes when it feels like it, which creates the struggle with helping the service department to even feel what I feel--and not think I'm nuts.