Hard to tell the cause. Here are some things you might want to try. Was the car working (not have this issue) prior to your changing components?

I would say that changing to deans is not the issue. I would do the elimination process. Put back the old servo. Does it eliminate the issue. Put back the old motor....etc. If none of these solves the issue, maybe you can do a range test on your radio. Is the radio batteries good, etc.