does Juice effect mpg computer?

[rrocket]

I have just over 10k miles on my 03 cc/da. I juiced it with the 4.61 about 5k miles ago.
When I compare my actual fuel used vrs. milage indicated by odo.It is much lower than that indicated by the on board computer.
I have been following posts and notice .5 differance ok.
mine can be off as much as 2/3 mpg. Stock tires.
Fuel filter has been changed.
Temp range was in the 40/70 degree range, and towing 17,000 combined.Good engine temps.
Trip showed about 15.7mpg. Fuel tank tells me about 13. Not loafing 70/75mph I had to keep reminding myself I had a trailer behind me.
Level 2 t/h mode.
Anybody out there had anything similar,or thoughts.All synthetics,amsol air filter.

Dam yankee in the South, but will never give in to the dam Commie attitude down here!!
My tags still say "Live Free or Die" Keep my Nh home.. Thanks ALL......

[Brad Pelot]

Yes it will affect the acurracy of the on board computer milage figures.I think the milage is fugured using a couple of different peremiters, including throttle possition, speed, and rpm.
The juice puts more fuel in at lower percentage of applied throttle, therefor fooling the computer (I think).
Mine is off at 3-4 miles per gallon on the freeway and averages at least 1-2 less than the computer shows.
Before my juice install it was fairly close.

[Elowe65]

Same here,

Just filled up
23.768 gal @ $1.59
onboard shows I used 22.1 gal but I put 23.768 in. Gal/mpg on left show what was pumped and gal/mpg on right show what onboard puter shows.

Odom Gal Gal Amt Pd Miles mpg mpg
122 0.0 $0.00 0 14.3
354 16.3 $26.00 232 14.3
691 21.9 $35.00 337 15.4
1035 22.5 $36.00 344 15.3
1357 21.3 $34.00 322 15.1
1711 23.1 22.7 $37.01 354 15.3 15.6
2095 25.0 24.8 $40.00 384 15.3 15.5
2430 23.1 23.0 $37.00 335 14.5 14.6
2727 21.9 $35.00 297 13.6
3079 23.8 21.8 $38.00 352 14.8 16.1
3442 22.5 21.1 $36.00 363 16.1 17.2
3790 23.1 22.1 $37.00 348 15.0 15.7
4102 19.4 17.8 $31.00 312 16.1 17.5
4509 23.1 21.7 $37.01 407 17.6 18.8
4859 20.6 19.5 $33.00 350 17.0 17.9
5156 18.8 16.9 $30.00 297 15.8 17.6
5330 12.1 11.0 $19.61 174 14.4 15.8
5667 22.1 20.8 $34.00 337 15.3 16.2
6003 21.3 19.3 $34.00 336 15.8 17.4
6352 22.5 20.8 $36.00 349 15.5 16.8
6650 20.0 19.5 $32.00 298 14.9 15.3
7004 21.9 19.9 $35.01 354 16.2 17.8
7411 23.8 22.4 $38.01 407 17.1 18.2
7797 23.8 22.1 $38.01 386 16.2 17.5