I am paying chidsupport and want to sign over my parental rights is that possible?

It will not you from having to pay child support, since that is a legal obligation, not a right, but you can ask, If the other parent and the judge agrees you can sign your rights to visit and your rights to have a say in the child's life up. But most likely you stopped using those rights long ago.

Whether its possible or not depends on several factors. But the reality is that no court will allow you to give up rights to get out of paying support. With the TPR will not be granted or the law states that a TPR does not end support.