What should I do if I mixed 92 and 95 gasoline once?

[VonMarcus]

Occasional mixing of 92 and 95 gasoline is acceptable, but long-term mixing should be avoided. The differences between 92 and 95 gasoline: The octane ratings differ, leading to varying anti-knock indices. Higher-grade gasoline provides better anti-knock performance. Effects of long-term gasoline mixing: Prolonged use of mixed gasoline grades will affect the lifespan of the vehicle's ignition system, fuel injectors, and spark plugs, potentially advancing the need for major repairs. Strictly speaking, 92 and 95 gasoline shouldn't be mixed, but since their chemical compositions are relatively similar with strong anti-knock properties, occasional mixing usually doesn't cause significant issues. After short-term mixing, special vehicle maintenance generally isn't required. However, it's recommended that owners use the specified gasoline grade whenever possible. Using 95 gasoline in a car designed for 92 usually causes no problems, but the reverse may lead to engine damage. Using lower-grade gasoline may cause engine knocking, and in severe cases, can result in bent valves or damaged valve covers.

[DeIsaac]

I was almost freaking out when this happened to me—mixing 92 and 95 octane gas once really gave me a scare. My car usually runs on 95, but last time at the gas station, I was in such a hurry in the queue that I accidentally added some 92, with the mix ratio roughly half and half. I immediately asked a mechanic, and he said modern car engine control systems are quite smart—they can automatically adjust ignition timing to adapt to different octane levels, so you barely feel any difference while driving. As long as it's not a high-performance sports car, there won't be major issues in the short term. Just avoid aggressive acceleration while driving and maintain a steady speed to let the ECU gradually learn the mixed ratio. Once the tank is empty, switch back to the recommended octane rating, and don’t make a habit of randomly mixing fuels. If you're really worried, drive about 200 kilometers and get the spark plugs or ignition system checked to ensure there’s no carbon buildup. In short, one mistake won’t ruin your car.

[ReeseAnn]

A friend shared that mixing gasoline grades isn't a big issue. The engine control system will fine-tune parameters to compensate for octane differences, possibly resulting in slightly reduced power but without safety concerns. The key is to immediately stop mixing fuels and maintain normal driving habits until the tank naturally empties. During this period, as long as there are no warning lights on the dashboard or severe engine vibrations, everything should be fine. Afterwards, simply refuel with a single gasoline grade to return to normal. Long-term mixed fueling is what poses carbon deposit risks.

[AndersonFitz]

I once accidentally mixed 92 and 95 too during my novice period, which was quite nerve-wracking. Immediately checked the manual to confirm my car doesn't require specific high-octane fuel before feeling relieved. Suggest driving normally but avoiding peak hours to reduce stress. Just use pure 92 or 95 after the current fuel runs out.