I don't feel a vibration in mine but something that I wasn't used to was the big V8 making the car wobble a little when I am stationary at idle. I think that is really cool though. Can't help you with the vibration.
I think you may be feeling the same thing I do. Call it a "wobble" or "shimmy" it seems to be at idle, almost like the car wants to get going and is getting impatient or something. Sounds like we both have the same symptom so maybe it's normal. I called the dealer's service department and asked them if they had any other complaints of this and they said there are too few of these out there and they are too new to tell if this is "normal." He will call GM and find out if anyone else has complained and what GM's disposition is. Could be the cam grind for all I know.
Yes the engine has a "lumpy idle". It's aV8 !!! it's a performance V8 !!! It's not a Buick. I'm not being a smart %^& well maybe a little. But the bottom line is there is no crossover tube in the exhaust. That helps balance backpressure from side to side and also lessens a lumpy idle. But you lose that old time exhaust note when a crossover is added to any exhaust.The GTO tries to bring back the old exhaust note of true dual exhausts. Also the LS1 does have a performance CAM. More overlap than a "BUICK", or any other common sedan. More overlap at high RPM is a good thing, at idle it makes the idle lumpy. I remember old high lift cams that if you could keep it idling within 300 rpm it was good enough. GTO's are great cars, BUT they are also MUSCLE CARS make no mistake. If you were expecting an AMG Mercedes type muscle it is NOT !! It's refined and has real suspension ( I'm somwhat suprised someone isn't complaining about the ride ) but it is going to let you KNOW it has a V8 performance engine under the hood. Many folks may have forgotten what a Muscle cars was or maybe many never did know, but I remember and the GTO is a very nice muscle car AND the LUMPY IDLE is part of it's Character.(Beach Boys said " Iv'e got a fuel injected engine sittin' under my hood.")
We have become so accustomed to the modern engines that have been refined so you don't even know the engine is running, if that's what you were expecting you may have purchased the wrong car. LUMPY IDLE is common in all GTO's.
And from Ronny and the Daytonas "When I turn it on, wind it up, blow it out GTO."
Thanks for the great reply. I'm not complaining at all. I think it's cool that my car feels "alive." My concern was more about proper balance and engine wear. I didn't even consider the function of the crossover pipe causing this. I will post what the dealer learns in about a week.
As promised I am posting the dealer's disposition about my engine "vibration" or "wobble" sensation. The manager and tech told me it was "normal" especially with such a large engine in a relatively small car. I'm not sure if I am buying this, but it could be true. His data base reavealed no other customer complaints of this nature. I still want to know if anyone else gets the feeling like it's really windy out when you are at idle. Normal is when it is like that with all the cars.
fellas, fellas. I can tell not too many of you have an old school muscle/sports car. The engine is loping due to the large cam. All old v8s did this. I love it. I even read a review online from one of the auto magazines that said that was their favorite aspect of the car. It's completely normal, and AWESOME!!