Tufoil does not cause oil to dissipate or vaporise. On the other hand on account of lower friction, engine oils run cooler and their lubricity strength stays longer.
We suggest that a engine compression test be done immediately.
Next, appraise the engine oil you are using. Is the viscosity too low like 0W or 5W for piston rings and cyclinder that have quite some wear ?
Check spark plugs, if they are wet.
Check radiator for traces of oil.
Check for oil leaks on lower part of engine.
Check temp on dash.
Check exhaust tail pipe for burned oil which show something like wet tar.
Dip stick level reading best done in morning before starting the car on level ground.
These are some of the things that ought to be investigated.