No 91 octane fuel in my area

[Jerry's XLT]

On April 9th, at a Chevron in Palm Desert CA, I paid $6.29 for 91 octane.

What's crazy about CA is that the refineries are in so. cal. and ship gas to Las Vegas NV via pipeline. In Las Vegas the same gas is always cheaper. Which means that CA gas tax is far greater than the extra cost of piping it out of state.

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[Itsdavebr0]

I typically get 94 from Sunoco and throw in a gallon or 2 of E-85 (I’m running a COBB tune) and noticed it shows knock on just 94 and it goes away with a little e-85.

 

[Wahjahbvious]

You're correct. Higher octane fuel does exactly *one* thing: prevents premature detonation of fuel in engines tuned in such a way that such detonation may otherwise occur*. That's it. All other benefits exist purely in the imagination.

Some of the confusion seems to stem from the fact that modern engines which "require" higher octanes will adjust their performance downward to compensate for lower octane fuel, so some people think that other engines must adjust their performance upwards in a similar manner. This is just Magical Thinking and does not reflect reality in any way.

*-you're unlikely to encounter predetonation at all in any modern engine, because of the aforementioned adjustments

Can I ask why you would put 91 in the Maverick. I have heard that the only real benefit is to prevent ping?

 

[Mavster Mechanic]

Even though, at high elevations, 85 may work I wouldn't trust going below the octane specified in my owner's manual. If emergency use, such as that was all that was available until you got to a larger market, as little as possible so you can dilute it.

Higher octane only matters under heavy loads or wide open throttle.

In daily life, if you only push the go pedal half-way down or less you could use 85 octane at sea level all day long.

 

[White Thunder]

I took this picture while fueling on Christmas day 2025 to show my gas choices. Very few stations have 91 octane. 89 octane is 71 cents more than 87 and 93 octane is $1.21 more. I use 89 octane a lot less than 87, grimacing every time. The gas door has an 87 label on it but I feel that I am not maintaining my truck. I'm WAY to obsessive about this. Note the 2.38 price. Four months later it is $3.98. Ouch!

I took this picture while fueling on Christmas day 2025 to show my gas choices. Very few stations have 91 octane. 89 octane is 71 cents more than 87 and 93 octane is $1.21 more. I use 89 octane a lot less than 87, grimacing every time. The gas door has an 87 label on it but I feel that I am not maintaining my truck. I'm WAY to obsessive about this. Note the 2.38 price. Four months later it is $3.98. Ouch!

Why use Premium when you don’t need it? All you’re doing is blowing out the exhaust.

 

[Mudduck]

On April 9th, at a Chevron in Palm Desert CA, I paid $6.29 for 91 octane.

What's crazy about CA is that the refineries are in so. cal. and ship gas to Las Vegas NV via pipeline. In Las Vegas the same gas is always cheaper. Which means that CA gas tax is far greater than the extra cost of piping it out of state.

61.2 cents per gallon is what California would like you to think the tax per gallon is. Here is a breakdown of the actual tax.
State excise tax: 59.6 cents (automatically increases july 1 each year)
Cap and Trade tax: 28 cents
Sales tax: 12 cents
Carb regulation costs: 23 cents (today), increases to 75 cents (MID 2026)
Underground storage regulation costs: 2 cents
Federal excise costs: 18.4 cents
Oil/gas penalty tax: tbd
Total per gallon ca gas tax: $1.43 today, $1.95 by Mid 2026

 

[Randorita]

I never had an engine that liked 85. I had to spend the extra amount to get higher octane to keep my engine from knocking. The last time I was in Colorado I had an Avalanche. It was not cheap to feed that beast!

 

[Tbone289]

Some of the confusion seems to stem from the fact that modern engines which "require" higher octanes will adjust their performance downward to compensate for lower octane fuel, so some people think that other engines must adjust their performance upwards in a similar manner. This is just Magical Thinking and does not reflect reality in any way.

I would encourage you to read about Ford's octane adjust ratio monitor. This is not "Magical Thinking", and in the case of the Ecoboost, it is indeed reality in every way. It does not "require" 91+ octane, will allow the use of 87 octane with no issues, and also take advantage of 91+ octanes for optimal performance. You might also refer to the owner's manual, which explicitly states this.

 

[Lone Ridr]

Since your president that we dislike up hear in Canada is spiking the sale of hybrids and one reason I bought my Maverick. I don't know how people are paying for all the bigger trucks. Can I ask why you would put 91 in the Maverick. I have heard that the only real benefit is to prevent ping? I used 91 for two previous AUDI S3 and S4 but it was required for those engines.

I would use 91 octane because Ford recommends it. I'm hoping they know something that I don't, HA! A born worrier. I won't drive one mile out of my way for 91 octane or ethanol-free, both rare finds in my area. I am slowly accepting 87 octane as my standard as it was for my Tacoma's and Colorado's. Alfred E Neuman What, me worry attitude.

 

[MaverickDragon]

Higher octane fuel does exactly *one* thing: prevents premature detonation of fuel in engines tuned in such a way that such detonation may otherwise occur*. That's it. All other benefits exist purely in the imagination.

Some of the confusion seems to stem from the fact that modern engines which "require" higher octanes will adjust their performance downward to compensate for lower octane fuel....

A higher octane rated fuel in a engine which "needs" it can run on lower octane fuel without damage as you noted, provided it hasn't been tuned to to where knock can no longer be prevented.

Running a higher octane rated fuel in an engine that can benefit from it means the engine can produce more power with a higher octane rated fuel, so that is a benefit beyond the anti-knock rating of the fuel, if the engine's power output is what you are after.

Fuels with a higher octane rating with alcohol to increase the rating have less power (fewer BTU's per unit volume) in the fuel, so, the fuel allows the engine to produce more power, but it will also use more fuel in the process. No free lunch in an engine.

For engines rated for lower octane rated fuels, you're right, the higher octane rating itself doesn't make a performance difference, but premium fuel formulations may also have upgraded detergent packages that can make a difference. Whether that potential is worth the price of putting it in the tank is another matter...

 

[Tim d]

I took this picture while fueling on Christmas day 2025 to show my gas choices. Very few stations have 91 octane. 89 octane is 71 cents more than 87 and 93 octane is $1.21 more. I use 89 octane a lot less than 87, grimacing every time. The gas door has an 87 label on it but I feel that I am not maintaining my truck. I'm WAY to obsessive about this. Note the 2.38 price. Four months later it is $3.98. Ouch!

Professionals say 89 is a waste of money. Curious why you feel the need for 91? I've used 87 in our ecoboost since new and we regularly tow a 3000 lb boat and also a sxs On occasion with no problems. Not to mention money saved. I do avoid gas that is not top tier though.

 

[kevinmccune]

I took this picture while fueling on Christmas day 2025 to show my gas choices. Very few stations have 91 octane. 89 octane is 71 cents more than 87 and 93 octane is $1.21 more. I use 89 octane a lot less than 87, grimacing every time. The gas door has an 87 label on it but I feel that I am not maintaining my truck. I'm WAY to obsessive about this. Note the 2.38 price. Four months later it is $3.98. Ouch!

does your truck need 91?,mine runs fine on 87 or 88 octane,yesterday it used 6.2 gals on 210 miles,funny thing I started putting high test in it till it was mostly high test and the mileage went to heck,which I couldn't figure out.

 

[Idahomaverick60]

Even though, at high elevations, 85 may work I wouldn't trust going below the octane specified in my owner's manual. If emergency use, such as that was all that was available until you got to a larger market, as little as possible so you can dilute it.

Octane is basically an "anti knock rating " in high elevation places 85 will act same as 87 on Florida. I was somewhere in the western mountains many years ago and premium only came in 90 Octane. Only place I have ever seen 93 is Florida many years ago. Herr we have standard 87,89,91 and for almost the price of diesel ethanol free 91

 

[zorki1c]

Why use Premium when you don’t need it? All you’re doing is blowing out the exhaust.

Yep. Right at the filler flap it says 87 octane. Why pay more?

 

[Lone Ridr]

Professionals say 89 is a waste of money. Curious why you feel the need for 91? I've used 87 in our ecoboost since new and we regularly tow a 3000 lb boat and also a sxs On occasion with no problems. Not to mention money saved. I do avoid gas that is not top tier though.

premium (91+ octane) is recommended for maximum performance, especially when towing or in hot weather to avoid engine knock. I haven't heard an engine ping since I got rid of a 2005 Chevy Colorado with an Inline 5 cylinder engine. That truck couldn't haul or pull 600 pounds without pinging. It was a truck in name only. The Mav would easily whip it's donkey. The computers of today precludes engine pinging so I am going to ignore Ford's advice and wean off high octane. All my motorcycles, current and past, recommend 93 octane. I use it religiously since the tanks aren't that big. In southern Illinois most of the stations carry 91 octane max, so I carry an octane additive in my saddle bags. My Big Dog Mastiff with a 117 Ci S&S engine and an S&S Super Sidewinder Carburetor has NEVER pinged or rattled due, IMO, to the fact I have always use 93 octane.

On another fuel note, I had to add STP water remover to the Maverick when I found the gas door popped open and water standing on top of the filler tube. You know, where the gas cap used to be. I don't want the gas line freezing on me next winter. I prefer proactive rather than reactive. Yet another Maverick annoyance perpetrated on me by the Ford Gods.

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