One button we’d noticed once daylight lit up the roomy cab was the one for engaging the Tow/Haul mode. Normally we would’ve avoided using Tow/Haul since, generally, that would make the trans stay in lower gears longer and delay locking up the torque converter—just what we didn’t need to save fuel. Not so in this case. With the F-150 it seemed to work completely backward from the norm, with the tranny staying in higher gears longer when in Tow/Haul. Any kind of hill therefore meant either flooring the pedal, forcing a downshift (or two) or disengaging the Tow/Haul to let the trans downshift more easily and less abruptly. We can only guess that Ford engineered it this way in an effort to prevent heat buildup in the transmission by minimizing slippage. There’s only so much torque in the Mustang motor below 2000 rpm anyway, so the drivetrain isn’t exactly stressed by the lower rpm.
Also on the fuel-saving menu, use of cruise control is said to help (not that we ever really believed that—except, maybe, with a pretty oblivious driver). Cruise certainly wouldn’t help our measly mpg figures, because at the 75 mph or so we were going with the trailer, the trans would never go into sixth gear. To get the upshift required letting up on the throttle a bit, at which point the tranny would shift, then we got back on it. Carefully. At 70 mph, the tranny would stay in high gear, but the motor couldn’t maintain speed at such a low rpm. Again, the trailer was a big, fuel-sapping sail.
Luckily, we had practiced all the newly learned fuel-saving skills by the time we were climbing the hills before Flagstaff. Otherwise it may not have been possible to achieve the 8.83 mpg that resulted from that leg of the trip. Yes, 8.83—not even 300 miles on a tank. This sure made us sit down (as if you have a choice while driving) and take notice. Coming to mind was a 1976 crew cab with a small-block and 4.10 gears we drove for many years. That vehicle was predictable, getting a solid 10 mpg whether running empty or towing with a cabover camper installed. Also, on this very same route, we generally see between 7.5 and 8.0 mpg with our regular tow apparatus, a 1980 Peterbilt with aerodynamics comparable to a typical single story home. Plus, the Pete’s moving 35,000 to 60,000 pounds, not the 10,000-something we were dealing with here.
It did make us wonder if perhaps we should pretend to be in California, adhering to the dumb 55 mph (truck) limit just to avoid going bankrupt before reaching our destination. At least the fuel prices in Arizona were superior to California’s.
It was a false victory to see an 11.51-mpg result at the next fill-up, since that stop was both a bit premature (but the last station for quite a while, and we did not trust the Miles-to-Empty wizard anymore) and the last one for the trip east. When the pump clicked off at $75 (29.8 gallons), we considered it close enough as it was now some 15 hours since departure. Just another hour or so up into the Rockies and we’d be done for the day.