Any idea's

[SubGothius]

Do not use dielectric grease on any of the electrical connectors or spark plug wires ~ it will screw up all the sensor & electrical signals ~ dielectric grease is non conductive !!!!!!!
https://www.todaysmotorvehicles.com/article/dielectric-grease-fights-electronic-signal-failures/

Erm, that article praises dielectric grease on electrical connectors, especially in modern cars with sensors, ECUs, multi-terminal connector blocks, etc. that may pass signals more "delicate" than the nominal 12V. The point of using a non-conductive grease is so the grease itself does not conduct any current between unrelated adjacent terminals or a ground. Any sound automotive connector will have enough firm metal-to-metal contact to displace the grease and conduct the signal.

Speaking of, on multi-terminal computer connectors and the like, I've used Stabilant 22. It's engineered to be conductive in the immediate presence of electric current like right where the actual contact points meet, filling any microscopic gaps between the contacts with a conductive fluid and effectively making it as good as a soldered joint, but otherwise it acts as an insulator. They used to run their computer at trade shows as a bare motherboard submerged in a Plexiglas tank of the stuff. One drawback: I gather it can facilitate tarnish formation between contacts of certain dissimilar metal combinations, so you only want to use it when you know the contacts are the same type of metal or a combination of metals not known to have this issue.