A scorched or "loose" UVC harness will be intermittent.
Can't be sure that's the problem though, but certainly worth a try.
Pull your driver side valve cover and make sure the harness is plugged in good and tight. You will be able to visually see where the little arms facing up are above the arm that holds them in or below it. Additionally you can see space between the connection then you know they're not getting great contact.
It will take you all of 30 minutes to pull the driverside valve cover since that's the easier one...
and that's where #2 and #8 reside
