We have a 2008 G6 with a V6 engine. About a month or so ago, the car started hesitating, almost a sharp jerking, when it gets to around 40-50 MPH. We took the car to the dealer where we purchased it and they were unable to find anything because there were no codes present. This obviously means we are imagining it, NOT. It doesn't happen every day but more days yes than no. It doesn't happen at lower speeds. Car has about 47K miles and has had all maintenance performed. Any ideas or things to look at would be appreciated.