Best MPG

[kyhunter89]

I started out getting 15mpg stock when I was just 17 (heavy foot, all the time). had 3,42's, first thing I got was a hypertech and it went up to about 17, then swapped to 3.73's and got 18, I moved out on my own and had no money so couldn't afford to break anything and I started getting around 19.5 on a 30 mile trip to work on country straight roads. Now I have a CAI, p&p tb and a few other things but I drive a little more aggressive and It never gets good milage in winter.

Id try ported the TB and a tune first thing.

[6.0vortecchevy]

personally I dont think gears are going to help.

Personally I think your wrong.

[Mang213]

Personally I think your wrong.

[Slick68]

Which grade of fuel is she using? A friend of mine has an 04 Sierra, 5.3, 60E, 3.73's all stock. With 87 octane, he barely got 14C/17HWY. He started using 89 octane and saw a dramatic improvement. 17C/19-20HWY.

[TA63]

Personally I think your wrong.

Feel free to enlighten us.

[TA63]

My 4.8 had 3.73s.... no help there.

Agreed. OP, open up the intake and exhaust, then get a good tune. Leave the gears till last.

[6.0vortecchevy]

Feel free to enlighten us.

Motor spinning higher rpm's more vacuum less strain= better mpg. In this case going from going from 3.73's to 4.10 would help mpg.

[6.0vortecchevy]

Agreed. OP, open up the intake and exhaust, then get a good tune. Leave the gears till last.

exhaust yes intake no. Intakes are just a waist of money. Cut some hole on the bottom of the air box and presto you got a 300 dollar air intake.

[kerrige]

I would prolly get a very inexpensive intake like 80$ on ebay higher flowing cleanable filter is the most important part. Intake tune and exhaust will be first.
Trav your right that muffler is prolly a little much for her. I need to figure out something a cheap that will improve flow and won't be too loud. Maybe the magnaflow and a second cheap muffler will be enough.
Gears are definitely down on the list, but still a future possibility. Also need to start making a little more money before I can start buying any of this stuff. I should get the RPO's today

[TA63]

Motor spinning higher rpm's more vacuum less strain= better mpg. In this case going from going from 3.73's to 4.10 would help mpg.

I went from 3.23s to 3.73.s with absolutely no change in mileage. I believe that the interstate speeds the op's truck spends most of its time running, anything more than 3.73s would be counterproductive.