Help! Which Fuel Octane Do I Use In My Ford F-150 or Chevy Silverado 1500? (Ask TFL)

Fuel octane selection in Colorado

What fuel can I use in my truck: be it a new Ford F-150, a new Chevy Silverado 1500, or any other truck? We recently got several question about the octane gasoline fuel requirements for newest trucks.

Kevin L. asks: “I have been debating to stay with regular unleaded 87 (89) or switch to premium 91 (93) for my 2017 Ford F-150?

Jayme K. asks: “I bought a 2020 GMC Sierra 1500 AT4 with a 6.2L. I knew it needed premium fuel, but I did not know it needs 93 octane premium.  I live in very southern Orange County – the very south tip of LA.  I have no access to any 93 octane fuel. What to do?

As Kevin and Jayme pointed out, the very first thing is quickly check your truck’s owner’s manual. You don’t have to open the glove box and crack open the big book. A quick internet search will provide a PDF document for your truck or car and your specific model year.

2020 Ford F-150 Fuel Requirements

Here is what Ford’s latest 2020 F-150 owner’s manual says on this subject:

Your vehicle is designed to operate on regular unleaded gasoline with a minimum pump (R+M)/2 octane rating of 87 or regular unleaded gasoline blended with a maximum of 85% ethanol (E85). Some fuel stations, particularly those in high altitude areas, offer fuels posted as regular unleaded gasoline with an octane rating below 87. The use of these fuels could result in engine damage that will not be covered by the vehicle warranty. For best overall vehicle and engine performance, premium fuel with an octane rating of 91 or higher is recommended.”

“The performance gained by using premium fuel is most noticeable in hot weather as well as other conditions, for example when towing a trailer.”

Indeed, Ford now gives the F-150 power ratings based on 87 octane fuel level. 91 octane is recommended for best performance.

Engine Knock

Simply put, a higher octane fuel has a higher tolerance against “engine knock”. Engine knock is when the fuel inside the cylinder chamber ignites unevenly or in several “pockets” or areas. This may damage the engine.

We have not done real-world testing specifically for different octane levels in the same truck/engine.

2020 GM 1500 Fuel Requirements

Here is what the latest 2020 Chevy Silverado owner’s manual says about 6.2-liter V8 gas engines fuel requirements:

“Premium unleaded gasolinemeeting ASTM specification D4814 with a posted octane rating of 93 — (R+M)/2 — is highly recommended for best performance and fueleconomy. Unleaded gasoline with an octane rated as low as 87 can be used. Using unleaded gasoline rated below 93 octane, however, will lead to reduced acceleration and fuel economy. If knocking occurs, use a gasoline rated at 93 octane as soon as possible, otherwise, the engine could be damaged.”

Indeed, many regions do not have access to 93 octane fuel. 91 octane is usually the highest available in those areas.

Chevy and GMC 6.2-liter V8 truck owners. What is your experience with using different octane level in your latest EcoTec3 gas V8?

Here is our most recent towing fuel economy comparison between a Ford F-150 V8 and a twin-turbo V6.