My 2002 Kia Rio shoots back when in reverse. What could this be it flies back

The brakes work it seems like the gas is being floored only when it's put in reverse in drive it's fine. It's like when in reverse it u controllable have to use the e brake to keep it from not smashing something

check for failed/broken engine mounts allowing either a vacuum leak(s) or linkage movement causing the throttle to move.