Intermittent camera. I go into reverse and it’s jittery and not smooth. Sometimes it’s gray and can’t see out of it and then sometimes black. Has anyone else had this before?

 

Locate the ground wire for the camera and temporarily remove it from the ground point then extend or use jumper wire and relocate it directly to the battery ground terminal, check and see if this helps or not. If the ground wire is integrated into a connector and you can't separate it, try to insert a probe pin into the ground terminal of the connector, then run a jumper wire so you can ADD and get better ground than the existing ground. A cleaned ground connection is all it matters especially on OEM camera.
If you can get to the harness, use electrical contact cleaner or 91% isopropyl alcohol and deep clean that.