My 6.2 is a 4x4 too. I have stayed pretty much even with an 05-09 Mustang GT in my setup yet pull the same basic mpg as you (12 average around town, 15 on long trips). You can do better on fuel mileage. The 4L60E does you no favors, but you can help your case with some 4.10s, maybe even 4.30s if you're 2wd and want to keep the big wheels.

 

And I drive aggressively too. The power is addicting, lol. I can get the average over 16 if I drive reasonably on the highway for a while. I drove 2500 miles one way and averaged 15.8, and that included a lot of idle running time. Just fyi. Need more torque!

 

what he said... MORE TORQUE!!!!!!!!!!

 

wow. now you guys really got me thinking. yeah my truck is only 2wd ill post up some pics in the first post real fast.

 

Wow 14? Granted I drive slow and use my cruise control around town, but I'm still getting 15 in my burban, and my silvy gets about the same, both 5.3's. I agree with the regear, the 4.8 is a fine engine, just needs some help.

 

Man something really doesn't seem right. I've got basically the same truck, though mines an 07 model, it is a 2WD-Z71 package so it came with the factory 3.73's and the A/T tires (265-70-17). I'm averaging about 16.5-17 mpg about 50/50 driving. I've seen 22-23 on the highway long travels and usually 13-15 in town. And these numbers are down a bit as I've got almost 100K miles on my truck now. When new I was able to average 17-18 mpg.

My mods in sig, which are few for me. I can't say that the truck is a powerhouse but it does pretty good. Would still like to add an underdrive pulley, vette servo, and maybe headers, but doubt I will keep the truck that long.

I know the 3.23's and 22's are probably hurting you quite a bit. I would also consider getting rid of the flowmaster for maybe a magnaflow or similar. Get rid of the superchips for a custom tune, and then bolt-ons and you should see a fairly decent difference. And the good thing as long as you don't go internal the bolt-ons will still work with a 6.0 or 6.2 if you decide that its not enough power.

 

have you ever thought about a basic turbo kit from one of the vendors? there are guys getting some good power out of the little 4.8's and you have the gears that could really make it nice IMO. only real thing you would need to do is build the trans, new driveshaft, upgrade the fuel system, etc. theres a lot of threads around with guys that have done it. sure its expensive but if i could do it i would.

 

Why can't you?

 

thought about going the turbo route, as im good friends with the owners of AGP Turbo here in tempe, and they are in the process of making a kit that would bolt on my truck. but i dont know if thats a route i want to go or not.

 

keep the 3.23 and get a turbo lol