01 silverado 4.8 vs 07 classic 5.3 tuned

[MrHeadshot1982]

nice run is your 4.8 bad on gas i got 2002 GMC with a 4.8 and she is real hard on gas after i did a tune up to.

[krazor8]

@MrHeadshot1982 i got a 2003 silverado 4.8l, no tune up, no oil change(likes about 1k miles till nect change),dual flowmaster 40 deltaflows, i routinly get 17 in the city and sometime 20 on the highway at 65, at 70 i get 19

[MrHeadshot1982]

@krazor8 thanks.

[krazor8]

@MrHeadshot1982 also forgot to mention, elevation does play a big part in hp and mpg, im in texas, my specific elevation is 5326 feet... as for being hard on gas after the tune up, id check over the plugs and make sure there ok