Help! My Cruze has been making a loud snapping noise when shifting (auto or manual) from 4th to 5th gear. It only does it when going up hills. Notice it when driving along at 50-60km/h and then need to pass or speed up - the car lags a bit then makes a loud snapping noise (like the sound of a metal deck chair being snapped open) and then the car takes off. Does not sound like it is coming from the engine. Been to the dealer 3 times and they can't recreate it so can't fix. Say it is excess fuel popping over the pistons. (not stupid - it isn't that) Anyone have thoughts ? It's a 2018 and should not have issues yet.