Sorry, I mis-typed. Meant to say 1oz/5gal.
Some people report better fuel economy and easier starting, others say it does nothing, and another group suspect fouled spark plugs and failed O2 sensors..
Lubricity of the fuel is often mentioned by people who claim their fuel pump has gotten quieter and some think it helps combat the effects of ethanol.
In my head it could make sense that oil in fuel could promote a better ring seal, improving compression and torque while reducing blowby in the same way a wet compression test does, but at such a small ratio I wonder if it has a measurable effect.
It's widely accepted that tcw3 oils have good detergency so may be effective as a continued use, maintenance dose style cleaner..but ultimately..
It's your car. Do what you want with it. But just read the owners handbook first and see what it says about additives. They might effect your warranty.