I was using the slap stick on my 2013 Chevy Cruz and while in 6th gear I started up a hill, on the highway, and the car continued to slow and would not take gas. I even pushed the pedal to the floor and it continued to slow, so I shifted back into automatic. I've tried using the slap stick twice and both times this has happened. Is this normal in the Cruze? Do you have to shift into a lower gear when going up hills? I have a Dodge Avenger that also has a slap stick and I have not had this experience with it. Should I be concerned or am I doing something wrong?