[PitCritter]

I drive a 2011 F-150 FX2 w/ a 5.0L engine

I have a question regarding the PCM “learning” process.

First, some background…

Most of my mileage is a 70/30 highway/city mix. I average around 17mpg. I recently got back from a long road trip. I towed my 28’ travel trailer from upstate NY to Miami via Memphis to leave it there for the winter.

Along the way, my first tank of gas got me 8.8 (gasp) mpg. As I kept going, my mileage increased every tank until I was at a far more respectable 11.3. Halfway to Miami, I stopped for a couple of days and explored Memphis. In town, I only put on around 50 miles (without the trailer) and my mileage didn’t recover all that much.

On my first tank with the trailer back on, my mileage was back down to 8.5. Once I got to Miami, my mileage was back up to 10.1.

During all of this, I was in Tow/Haul, 6th gear locked out, at 55 mph.

I spent a couple of weeks in Miami where my in-town mileage went up to around 15mpg.

When I left for home, I fuelled up and immediately hit the highway (without the trailer). It was over two hours before my mileage hit 18. After that, it climbed steadily until I was getting 22+ mpg at 70 mph while driving through the West Virginia mountains. This is amazing, since I generally struggle to hit 20mpg at 60mph on level highways.

OK, after all that, the question.

Does the PCM learn or adjust to a style of driving? It seems that every time I drive a few miles in the city, the truck forgets how to drive efficiently on the highway.

If that’s the case, would a programmer allow me to take a snapshot of the PCM in highwat tune and re-load it when I wanted to do a highway run?

With that being said, if I drove a couple of tanks strictly in the city, should I expect my in-town mileage to increase too?

I’ve also heard that if you try E85 (not for me, thanks), you shouldn’t expect the truck to settle down for a couple of tanks. Same kinda’ thing?


These may be newbie questions, but please educate me.