If knocks are not apparent, your engine's computer had adjusted to the gas grade, but don't do it permanently. The ECU won't guarantee 100% success rate. Micro injuries to your engine may accumulate which will eventually surprise you one day.

As a precaution shift to a 'conservative type driver', avoid hard-aggressive driving, very heavy traffic situation, steep climbs, and overloading.

Bigay mo na lang kaya sa kin gas mo para wala ka na problema