Terrible MPG

[Quijy]

After I tuned the ECM, Magnaflow and CAD I am at 11mpg city solid on 87 fuel and 14 to 15 mpg highway depending on terrain and weather on 87 fuel.

[Big.Z.hummin]

i'm at 10.3 currently and thats with m/t's oversized brushguard and gobi rack. i always run 89 octane because maybe its just me but i feel a huge difference between low and mid grade. when i run 87 my engine sounds like its working overdrive and screams up hills. maybe it just mine. anyone else experience that?

[theBaron]

with a stock truck, i have never gotten worse than like 9.8, thats with me just driveing the hell out of it, and when my wife drives, she gets low 11,s this is average mpg..

this is stock, with 35 inch M/Ts..

[MVR 155]

I would have to agree that 7.5 mpg is pretty bad, when we had our 2006 we got 10.5-11.5 with mixed driving (majority of it around town) depending on weather obviously being worse in the winter with letting the truck warm up etc.... On the highway we got 13-14.5 depending on cruising speed. So far with the 2008 it looks like we are getting closer to 12 with the majority in town (short trips) but I have only run 1 tank of fuel since getting it a few weeks back.

[BUMMER]

Do you think the AC delco plugs could be causing such bad MPG? Which OEM brand did the 2003's come with from the factory?

[OrangeCrush]

I know you said you were on stock wheels but do you have stock tires?

I'm not trying to play semantics but taller tires will make you lose 2-3 mpg.

Mark

[BUMMER]

Mark, my tires are stock BFG's. My mpg today went up a bit from 7.5 to 7.9 lol