What happens if you put regular gas in an Acura TL?

Using regular gasoline in an Acura TL that calls for premium can lead to reduced performance and efficiency as the engine retards timing to prevent knocking. The car will usually run, but you’ll notice slower acceleration and lower fuel economy until you refill with higher-octane fuel.

Most Acura TL models, spanning the 2004–2014 generation, are designed for premium unleaded gasoline with an octane rating around 91 or higher. If you accidentally fill with regular (87 octane in the U.S.), the engine’s knock sensors may pull timing to prevent detonation, which can dull power and efficiency. While a single tank won’t usually cause immediate, catastrophic damage, repeated use can stress the engine over time, and you’ll want to switch back to premium as soon as possible and drive conservatively until you’re back on the proper fuel.

How the Acura TL uses fuel octane

Understanding what octane does helps explain what you might notice after using regular fuel. Higher-octane fuels resist premature detonation under compression, which the TL’s V6 engines are tuned to handle. When the octane is lower than recommended, the engine’s knock sensors may retard timing to prevent knocking, resulting in less aggressive power delivery and lower efficiency.

Here are the practical effects you’re likely to notice on the road:

• Reduced power and slower acceleration, especially when climbing hills or when you demand quick bursts of speed.


• Possible pinging or knocking under heavy load or rapid throttle input; the sound, if audible, is a signal that the engine is protecting itself.


• Lower fuel economy because the engine cannot operate as efficiently with the timing adjustments.


• Timing retardation to prevent knock, which can raise exhaust temperatures and further affect performance.


• In rare cases, persistent detonation or misfires can trigger the check engine light, prompting a diagnostic check.


• No immediate catastrophic damage for a single tank, but repeated use of regular fuel is not recommended and could contribute to longer-term wear.

In practice, if you accidentally fill with regular, you’ll typically notice diminished performance and efficiency right away under demanding driving. The car will still run, but you should refill with premium at the next fill and drive normally after you’re back on the correct fuel.

What to do if you’ve used regular, and how to prevent it

If you’ve just filled with regular, follow these steps to minimize any negative effects and restore optimal performance.

• Fill up with premium at your next fuel stop and avoid aggressive driving for the first few miles as the engine relearns optimal timing with higher-octane fuel.


• Avoid heavy acceleration, high RPM, and towing or steep climbs until you’re back on premium and you’re not experiencing knocking.


• If you hear persistent pinging or the check engine light stays on after refueling, have the vehicle inspected by a technician to rule out knock-related damage or misfires.


• Octane boosters can raise octane temporarily, but they are not a substitute for consistently using the recommended premium fuel. Rely on premium for sustained performance.


• Mixing a small amount of regular with premium is generally safe, but it does not raise octane beyond what the tank already contains; the best practice is to use premium and avoid regular for the rest of the tank.

After refueling with premium, the TL should return to its normal performance within a few miles of driven mix, assuming no knock-related damage occurred. If performance remains diminished after several tankfuls of premium, a diagnostic visit is warranted to check for potential engine issues.

Model-year notes

TLs from different years share the general requirement for premium fuel, though exact octane recommendations may vary by market and model year. In the U.S., early 2000s TLs with the 3.2L engine and later 3.5L versions typically specify premium unleaded gasoline (91 octane or higher) to maintain best performance. If you’re unsure about octane requirements for your specific year and market, consult the owner’s manual or the fuel-label inside the fuel door for the exact specification.

Summary

In short, regular gasoline is not the ideal choice for an Acura TL that is designed for premium fuel. Expect reduced power, slower acceleration, and lower fuel economy when running regular. The engine will mitigate risk by retarding timing, but this comes at the cost of performance. If you accidentally fill with regular, switch back to premium at the next refill and drive conservatively until you’re back on the correct fuel. For best results, follow the manufacturer’s octane recommendation and consult the owner’s manual if you’re unsure about your model year.

What happens if I accidentally put regular gas in my Acura?

Accidentally using regular gas in an Acura designed for premium won't cause damage but may reduce performance.

Can you put regular gas in an Acura TL?

Acura vehicles are designed for high performance, and fueling them with premium gas is sure to keep that precision engineering going for years to come.

What happens if I put 87 in my Acura?

Possible Engine Knocking: Lower-octane fuel can cause engine knocking (a knocking sound), which can be damaging over time. Lower Fuel Efficiency: Regular gas may not burn as efficiently as premium fuel, which can cause lower miles per gallon (MPG).

What happens if I use regular gas in a car that requires premium?

Using regular gas in a car that requires premium can lead to engine knocking, reduced performance, and potential long-term engine damage over time. The engine's knock sensor may compensate for the lower octane fuel by slowing the engine's timing, which results in a loss of power. If your car's manual states premium is only "recommended" and not "required," the effects may be less severe, but using the correct fuel is always best. 
Immediate and short-term effects

• Engine knocking or pinging: This is the most common symptom, caused by the lower-octane fuel igniting prematurely under pressure. 
• Reduced performance: The engine's control system may adjust to a "safe mode," which can decrease horsepower and torque. 
• Less energy: While not a significant difference in most cases, lower-octane fuel may provide less energy. 

Long-term effects

• Engine damage: Consistent use of regular gas in an engine designed for premium could lead to damage to components like spark plugs, valves, and pistons. 
• Voided warranty: Using the incorrect fuel, especially if the manufacturer specifies "premium required," could potentially void your car's warranty. 

What to do if you accidentally put in the wrong gas

• If your car requires premium: Avoid hard acceleration or climbing steep hills until you can get premium fuel in the tank. 
• Mix fuels: You can add premium gas to the tank with the regular gas to raise the overall octane level. 
• Consult your owner's manual: This is the best way to determine if your car requires premium fuel or if it is only a recommendation.