04LS1 5.3 more fule mileage and power

[Ryanezek36]

I admit Im an ameture at this. Im looking for a good base tune for my 04 GMC sierra with a 5.3 that will give me better MPG and more power for towing my race car. If someone could send one to me or sell one i would greatly appreciate your efforts.

[5FDP]

Rarely will you gain much mpg from a tune in a gas truck. A proper tune up would be good idea aswell. Clean the MAF, air filter, new spark plugs, new o2 sensors, clean throttle body, intake gasket and knock sensors if it's over 100k miles as they tend to fail past 100-125k in some cases.

Gear ratio and tire size can affect mpgs too, I'd just assume 3.73's, those would be the best all around gear for cruise rpm and for towing. 16-17in rims are lighter and I'd guess you have the factory stuff on there already, but if not bigger rims and tires will reduce performance and mpg.

Past that, learning the ropes and seeing what can be changed can net you a better performing truck. Factory power enrich settings are really "lazy" and some torque mngt could be taken away to improve performance. Also increased shift times and pressure can do alot for overall truck feel and performance.

[Ranger6202]

timing is key when wanting more power and MPG.