Can I add 95 octane fuel when 92 octane is not completely used up?

[VanAngelina]

It is possible to add 95 octane fuel when 92 octane is not completely used up, but prolonged mixing of different gasoline grades should be avoided as it may negatively impact the vehicle's performance. Issues such as engine knocking, insufficient power output, and increased engine wear may occur. More details are as follows: 1. Many car owners have experience mixing gasoline, most commonly 92 and 95 octane. Occasional mixing (once or twice) will not affect normal vehicle operation, but long-term mixing can lead to knocking and power loss. 2. Prolonged mixing of gasoline grades increases the frequency of engine knocking and accelerates engine wear. 3. If the vehicle's standard fuel requirement is 92 octane, prolonged use of 95 octane fuel may cause carbon deposits to form in the engine over time. 4. The cleanliness of gasoline is determined by national standards, not by the octane rating. The octane number represents the fuel's resistance to knocking—for example, 92 octane gasoline contains approximately 92% isooctane, while 95 octane contains about 95%. Higher-octane fuels have better anti-knock properties due to the higher isooctane content.