Suburban jerking badly on acceleration after start
 

2014 Suburban with 95k Miles. Anyone who can provide insight or troubleshooting for issue greatly appreciated. We bought this car used with 10k miles and is the Family Truckster. Really hoping to put another 50K on it before trading in and worried as to what the issue is.

Reproducibility Steps
- Start Truck
- Put the Truck into Reverse for 50 Feet (ex. Backing out of the Garage)
- Put car in Drive, then accelerate normally through 10mph, assuming 2nd gear?
- at approx 10 mph through 12 mph the vehicle will jerk twice while accelerating
- continue to accelerate through 20mph, the car will do one of two things:
- More often (Thunk into the next gear, very bad shift into that gear) or if accelerating more rapidly
- the shift will almost seem to, if person was driving a manual, drop the clutch.

This only occurs given the steps above. If you continue to drive the issue described above doesn't happen until you shut vehicle off and then repeat. You must shut it off in order to reproduce without fail.
SIDE NOTE: This initially started with way more violent jerking which initially thought OMG Tranny is going, so we rushed it over to chevy thinking we may be covered by PowerTrain, hence they recommended the tranny flush which lessened the issue a bit but still annoying and present.

Work done at Chevy Dealer and Local Good Year
- Chevy recommended a Transmission Flush (Rolling my eyes) OK did it. Issue persists
- Good Year, new transmission mount,
- replaced Throttle body with new Throttle Body Position Sensor

I replaced
- Mas Air Flow Sensor
- MAPS Sensor