Thanks! I'm interested in anything that might help.

 

well, my eyes and head hurt.

ok there was lots of info I found and more than I care to write. so I will cliff note it the best as possible.

if truck has less than 20K it will improve after break in
suposedly the dealer can reflash with an economy tune or something.
swiss cheese air box/aftermarket intake and free flow exhaust help greatly.
max mileage and other modules that advance timing help greatly.

Now I noticed that 05-06 owners were the ones mostly complaining about mileage. but there was some that said they get hand calced 16-19mpg on stock trucks.
also some peoples MPG went up quite a bit after using some power service or other type additive.

there was some wingers on there. Some peeple were saying they got 20mpg all around. Sorry but I dont buy it. maybe if they were looking at the overhead. I averaged 21 once but it was empty and down hill the whole ride and never went above 60.

also. if you have 4.11 gears that doesnt do any favors either.

but after all of my looking I didnt see anything that said the 05s suck.

I did notice that smog protection was a factor as well

 

I'll bet the complainers are driving around with 35's under a 4~6" lift. both of which will kill your mileage. If I had stock tires on I'm sure i'd be pushing the low 20's. when I put my 105 lb tire/wheel combo on I lost about 2~3 mpg. before I did that upgrade, I was getting 17's & low 18's. Now, 65k miles later, I'm back up into the low 18's. granted the tires are worn and are lighter than they used to be, I'm sure this is also helping the #'s some. not sure how much longer I'll be on them but when I do go over to the newer 33's I'll post the results in that mpg thread of mine...

 

actually the complainers had 33s or less. but hell I have 33s and I still see 16-19 all around. and all I have is a ROKK tech, amsoil 4510 airfilter and an aero turbine muffler. I bet I could stay in the 18-20 with the max mileage box.

 

and... I'm considering jumping up to the 35's... and doing a gear swap to the 4.11's. I did that with my 2000 gasser and was consistently getting upper 13s low 14's. I think my mileage would be better with the 4.11's and the tall tires vs the stock gearing & taller tires.

 

most definatley it would

I think that swhy I didnt really notice any MPG decreses when I went to 33s. I also went from stock steelies to H2 aluminum. so the weight is about the same. but rolling friction is worse of course.

 

I'm only running 33's. Everything is stock except that I had to cut my cat off because it was plugged. I have 3.73's, so I don't know why I can't get better than 14-15 mpgs. I'm hoping the brew and the new Max Mileage box will help. It should be here tomorrow. I'll keep you posted.

 

ah, the truth comes out... dude, get an aero 4040 and put it where the cat was and you'll get another 1~1.5 mpg. i had a straight pipe & 30" magnaflow installed and lost 1~1.5 mpg, then 6 months later, added the aero and got it back. your egt's will climb a little but you should have no problems with that setup, it's far better than stock. I was also down in the 14's with that setup...

GRI... if I went to the 4.11's with the existing tire size, might still work out better than the 3.73's. what do you think? IIRC the stock tire diameter was 30"...??

 

just found my mileage spread sheet... I lost approx 2 mpg with the tire change.

 

Sure wish you lived near me. I have 4:11s and want lower gears, OH Well.