Yes, it will not harm catalytic converters or oxygen sensors, and will clean/remove deposits in port injected, direct injected, and carbureted engines.
Max-Clean is suitable for use in all liquid automotive-type fuels, including gasoline, ethanol, diesel, and bio-diesel.
When used at our recommended dosages, Max-Clean will stabilize fuels with less than 10% ethanol for up to 2 years. For fuels containing 10% or great ethanol content, Max-Clean will stabilize for up to 1 year.
No, but it will prevent it from degrading any further, and allow it to be safely used without forming engine deposits.