I’m running 93 now too. I get 21 mpg on the highway; 17-18 mpg in mixed driving. Just dropped $45K buying this XLT, and as my first new vehicle in 37 years I’m gonna baby it.
With the 36 gal fuel tank I save up a bunch of fuel discounts from grocery shopping and cash them in for a $.30/gal or $.40/gal savings on the 93.

 

I've been running 87 ever since I got it. No pinging, 16 mpg city, high teens to mid 20's highway. I did hit 30 once ( hand figured it was 27) but that was with a tailwind. The next day the wind switched directions; 13mpg.

 

2018 Lariat - 2 reasons I run premium in all vehicles. First, I am retired and the wife and i are pretty much home bodies. Vehicles sometimes do not go out for weeks at a time. Gas loses Octane over time even with conditioner which I use. Second, going on vacation towing a boat, I have found that the truck does very well in manual in 8th gear. When pulling a slight incline with regular gas in speed control I could hear a slight ping. Premium gas eliminates this. Truck just runs better in my experience.

 

Almost 70K miles on the truck, with 60K of that mine, and after driving it a few weeks using 87, I switched to 89 just to see what would happen. The truck pinged quite a bit on 87 and the engine made a good bit of noise just driving slow in a parking lot or when cold. Running 89, the pinging went away and not so much noise when cold or idling I believe. The pinging was my biggest gripe. I used to have a '08 Mustang GT that did the same thing on 87...ping like crazy...couple points of octane quieted it right down.

 

My 2019 5.0 runs and sound like crap on 87. 91-93 no pinging runs better. Average 19.5 mpg overall hand calculated. Now I’d it would just stop burning 1.5 quarts of oil between regular oil changes …..

 

What's a regular oil change?

 

about 7000miles . I do mainly highway driving usually about 25/30% left on OLM

 

UPDATE

I have 80K+ miles on the truck now and I have been running 87 octane for last 2 tanks with zero pinging. What changed is....I started getting codes for mis fires on cylinder 5 and 3. I took it in and the dealer told me that the VVT solenoids were bad. It was covered mostly on warranty so I let them do the work and immediately noticed a performance increase and while checking local stations for alcohol content, pumped a tank of 87 octane to see if the solenoid changes would correct some of the pinging I have been noticing since I bought the truck. Now on second tank of 87 and zero pinging and idle is quieter also. I suspect the VVT solenoids were bad from new. Still monitoring..and I will likely put in 89 later on to see how the truck responds to that at some point. Cal me crazy but there might have been a small mileage increase also..still verifying though.

 

With automotive gasolines, some of the light hydrocarbons (e.g., butane) will evaporate from it over time, which will only slightly lower the octane level. But that is over LONG period of time, not just a few weeks or even months. It would take two years or more just to lose a single octane number. Not driving a vehicle for weeks or even months on end will NOT result in lower octane.

Unless your engine is knocking and pinging OR unless your engine is specifically designed to perform better with higher octane fuel, using anything other than the minimum octane level that the engine is designed to use is accomplishing nothing more than emptying your wallet for no real benefit.

Yes, exactly why you'd run premium. Now if you didn't tow very often and the engine was not pinging when you weren't towing, there'd be no need to burn higher octane fuel except for those time you were towing.

I'm no engineer, but I used to work for a downstream petroleum distributor. My company delivered fuel to commercial and retail customers in ~38 states.

 

Good choice.

Engine "ping" happens when the air/fuel mixture in the cylinder is wrong and it burns unevenly. It can literally cause permanent damage to internal parts of your engine. While too low of an octane fuel can cause this, there are other causes, including bad spark plugs, engine timing issues or carbon buildup.