If you are concerned about it take it to the dealer. I am amazed how lazy some (Note I said some) service writers are when it comes to getting your new vehicle to spec. Afterall you just plunked down some hard earned$$$ and you are not out of line to ask them to make your vehicle run like it is supposed to. Check engine light or not, take it in. Your sounds alot more rough than mine and I would not wait.

 

I agree some of them make you feel like you should be somehow honored that they even talk to you when they find out it may be warranty repair.
I don't assume they work for free when it is warranty. Wish me luck to find some good service guy.
Thanks guys for all your responses. I will take it in and see what happens. I will post the results.

 

You’ll find that if you test drive a similar vehicle it will most likely act the same, this is normal and requires no repair. The emissions calibrations required to meet California's strict standards necessitate a leaner on-idle fuel ratio, this can cause a slight chop at idle depending on outside temperature and altitude (worse the lower you are).. This calibration increases the exhaust temperature which reduces tailpipe emissions, it turns the by-products of combustion into soot which is blown out the exhaust pipe (in very small amounts) and causes the tailpipe to accumulate the black deposits more so than a federally spec’d Tahoe.

 

Thanks, ok this is answer that makes sense (comparing to answers from service department). It makes sense technically, but if I compare to my other V8 equipped vehicle that runs smooth (and always had - 02 Dodge Ram with 4.7L and 00 Dodge Ram with 5.2L) why would the new Tahoe run this way ? Did the already strict California standards got even stricter, therefore forcing the manufacturers to make adjustments that cause the
rough idle? I am really concern with the idle and shaking and the answer I just got from one service advisor was that the rough idle is not normal, but mileage on my Tahoe is low and it needs more time to break-in because the engine is still tight. Does this make any sense to you guys?

 

Sounds like that service advisor is full of pooh pooh to me. ZX's explaination sound logical to me, but sounds like your motor is shaking more than normal. Maybe you have a bad motor mount??????????????????

 

I searched the web and came up with a car talk mechanic that says the rough idle is due to the lean fuel/air mixture needed at idle to meet the most stringent emissions requirements ( I'm in California where they are stringent). Mine idles rough too, been back to the dealer twice and got the same "put more mileage on it" . Oviously Chevy is schooling the dealers on what to say about this issue. I'm averaging 16.5 MPG with 15,000 miles on it, and it idles rough the whole time.

 

Update. I no longer get any vibration. I guess my engine is broken in now.