The last few times I've been back to my parents place, I've noticed some fuel mileage improvements, particularly on the way there but not as much on the return trip.
Since Christmas of last year, I've installed an electric fuel system, D60, an intercooler, and switched to Schaeffer's 9000 5w-40.
I have logged every fill-up (167) since I bought the truck over 3 years ago.
Until recently, the best mileage I've had was 22.18 mpg
on the 7th fillup after I bought it. Usually though it was around
The other day I got 23.05 mpg
between Racine, wi and Lebanon, In. I used I294 around Chicago.
The last few trips have been:
Sept birthday party:
The city mileage has also improved slightly from ~13 to ~14-14.5
You can see on the graph when I installed the 40 gal rear tank.
Before that I was running only on the front tank.
Now, I have been having a problem with off-idle acceleration. If I'm not careful, the truck will totally black out the road instantly. This may be because of the intercooler causing boost lag, but I have not have the time during daylight to explore that yet. Once the engine gets to about 1600-1800rpm, it is just as responsive as it had been with no more smoke than I remember.
Due to the excessive smokiness on off-idle acceleration, I have had to back out of the pedal when starting to roll. This may be a factor in the improved mileage, but I know it is not all.
An intercooler and e-fuel increased my fuel mileage. Your results may vary.