Remove the 4 torx screws from the upper manifold cover plate. Then you can unclip the plastic mount the 10 pin connectors are secured to. At that point, you can remove the upper manifold if that was what you wanted to do. Once the upper is off, the 10 pin connectors are much eaiser to work with.
If you intention was simply to disconnect & clean the connector contacts, there is more to do. If you look carefully, the sides of the top connectors have fingers that engage a ridge on the bottom connector. A pair of large nails inserted uder the fingers will help lit them off the ridge so that the connector can be separated with less force. Some WD 40 will help too.
