PARIAH

87 most of the time. Higher when pulling.

Countryboycansurvive

Don't run the 85 octane they sell in higher elevations. You can get away with it in a N/A engine, but your Eco isn't affected much by the lower atmospheric pressure. Need at least 87.

FlameBlueFX4

93 with a splash of e85(about 5 gallons).

2011FX4boost

93 Octane and only Shell. Probably because there is a station right up my street and because I work for Shell Oil Company Before you ask, no I do not get a discount! Most people assume I do. Trust me, they want my money just like yours.

marauder11

Have wonder this a few times. Does anyone use regular and add octane boost. I go to a few small campsites where regular is all that's available . I have added premium and used octane boost and do not notice a difference in mpg or performance

jcain

Overthe counter octane boost is snake oil. You need to step into a real product like Torco or similar, but be aware of the potential hazard to emission components.

Adobe2X

I am soon going to tow about 7,000 pounds for several thousand miles on vacation. I may very well bite the bullet and use premium only on this trip.
With my old TT at nearly 9,000 pounds and on 87 octane, I was only rarely able to get more than 8 mpg.
Even on 87 octane and my new lighter TT, I am able to get 9 or 10 mph with ease. It may very well be interesting to see what the results are for 91 octane.

SkiSmuggs

I did a 6000 mile trip with a 9500 lb fiver last June and used premium the whole way as recommended by the manual. Even with some very hard pulls, I had no issues and averaged 10 mpg.

johndeerefarmer

It's not snake oil. It just raises your octane level by only about .1%.
Torco just raises the octane level a whole lot more than STP or the other regular products.

I run 93 year round now. I don't like the price but I tow a lot and am tuned and would rather be safe than sorry.

Besides as SKI says, Ford says use premium when it's hot and/or you are towing. I do both- at the same time.

PawPaw

At or below sea level and humid down here so 87 seem's to do just fine. I always use Shell or Valero and stay away from the offbrand's.