Sunday my father in law left his light on on his hhr ( told him to use the auto but he thinks it doesn't work). I used my impala to jump his hhr which isn't the issue at all just giving some back story. His preacher help move my car for me being I was stuck between the car and his back door cause the hhr has its batter at the spare tire. When he put it in reverse my engine very noticeably rocked back towards the firewall then back to its normal area. Is this normal or is it a sign of a bad mount? That was the first thing that popped in my head but I want to be sure.