When I open my powered hatchback of my Toyota Sienna on cold mornings, it power raises, but will often then power lower (fall relatively slowly, but firmly - keeps pressing downward even if someone is under the hatch). In a way it seems like the hatch "hits" something at the top of its raising cycle, but there is absolutely nothing above it. It happens whether I open it using the hatch's physical handle, the button in the car, or the remote. It seems to only happen when it is cold. One other piece of information - this began to happen after my original struts were replaced because of a recall. Toyota says that since it doesn't happen in front of them, they cannot fix it. Is the best/first thing I should try to replace the struts? How likely will it be that replacing the struts will solve the problem? Is there anything this can be other than the struts?