What can I do to get better mileage? I am changing plugs and wires tommarrow. I heard that if I change the upstream o2s i will get better, but how? I don't have any codes so will that work? Someone also told me to go synthetic because it will get better mileage. I am ordering a volant CAI and GMPP touring exhaust and hoping that will hook me up a little, i would be happy with 18's truck info is in my sig.

 

My wires are 7 years old with 150k miles on them and I don't plan on changing them anytime soon.

Avalanche's are heavy bitches. If you can find a way to lose some weight that would be a good start. NGK TR 55's are what a lot of people run for plugs. Get a custom tune, that will help a bit.

 

Stock rims/tires?

 

yeah ltz 20's

 

I also have a little miss at idle which i think is plugs and wires but I am not getting a light

 

Its a truck. What kinda of driving city/hwy mixed? That makes a big difference. If its mostly in city, then don't expect that much! Plus how do you drive it? What speed at the limit or below? How you drive makes the most difference in MPG.

 

its mixed driving and i average around 60 65 mph daily, 75 or 80 on road trips/hwy

 

changing upstream o2's is done because as o2 sensors age they tend to get lazy, they may not set a code, but they aren't running at their peak.

 

So you think they need changing? I would think that would give better gas mileage.

 

If you get a tune, you can have the O2's deleted.