I have a 2011 Chevy Impala. Once in a while the engine will rev and then kick into first gear. If I slowly press down onto gas petal it will not do this. If I start slow no problems, but if I put foot down on pedal hard it does sometimes. Can anyone tell me why this is happening?
I'm sure you've had this resolved by now, but as a GM trans tech I can tell you the most likely cause is a failed pressure control solenoid. The solenoid coil accumulates ferrous debris and becomes less effective. The pressure is commanded down at low speed and when the controller commands a higher pressure to take off, there is low pressure for a moment until the solenoid opens up more fully. The side cover has to come off of the trans to replace it.