Applying a lube to injector O-rings can be controversial …. or not. It depends on your tech sources and the O-ring base material.

One would assume most injector O-rings are made from a man-made material (nitrile, butyl, Viton, silicone, etc.) and not from natural rubber, but which one? The ideal lube will allow convenient installation/disassembly, provide an air-tight seal and not deteriorate the O-ring.

Here are some material pros and cons:
- Vaseline/petroleum jelly - petroleum based; jelly>liquid at skin temp.
- Engine oil,, WD-40, lithium grease - petroleum based. heat resistance varies
- Synthetic grease - high heat resistance
- Dielectric grease (e.g. Dow 4) - not silicone-based
- Silicone grease (e.g. Dow 111) - silicone based; high heat resistance; if sensed by the O2 sensor(s) (odds?), could render inop.
- Anti-seize paste - high heat resistance
- Palmolive soap - good for installation; tougher to disassemble

There are reports of fuel injection system cleaners affecting FI o-rings as well.

Complicating the issue are many opinions in the multitude of websites that either approve or disapprove each of the above materials. I'd rely more on information from engineering and manufacturer's white papers.

To be safe, I would suggest following recommendations by the FI O-ring manufacturer.

Sherwood
SeineSystems.com