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gas mileage = sad face :(

5376 Views 29 Replies 13 Participants Last post by  reggiecab2000, 
reggiecab2000
If you look in my signature you could see many potential reasons for my poor gas mileage but I swear its the truth that doing every single one of those things has not changed anything in my mileage it has remained the same...
i used to have just the throttle body spacer and cold air intake and flowmaster exhaust with stock tires no lift and still could never hit more than 15 mpg...
even with gears, lift, tires i still have the exact same mileage which usually varies from 13 to 15 mpg, this is a V6 btw...
my last 2 tanks however have been shockingly awful... ive been about 11.5-12 mpg and i dont know why!
i just replaced my fuel filter, i have recently replaced plugs, wires, cap, rotor, oil, oil filter (fully synthetic for years now), sprayed my throttle body, cleaned my k&n filter....
and i still cannot understand why my gas mileage is so poor i also recently seafoamed my gas tank and, a few times a year i am normally throwing in 44K (dads pick)
But i have noticed over the last few months a minimal (noticeable to me) loss in power overtime and i havent seemed to gain it back yet...
I really am going crazy with a 26 gallon tank that i have to refill after 320 miles.... do the math
does anyone have suggestion/help/comments for me?
I am wayyy past my high school gunnin the gas years and hardly ever beat the pedal unless necessary...
but i am fed up with this mileage.
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Ethan
I can't find gas here in Austin that doesn't have 10% ethanol in it, and it's killing my 94, eats up my injectors and kills my MPGS. Stupid government nazis.

I think your lift kit, and that 4.11 rear end is eating your gas mileage, despite what you think. And, if you like to accelerate quickly, and by quick, I mean getting up to 40 mph in a 6-7 seconds, then it'll eat gas quick too. With these trucks, you have to drive like a grandma.

^^ I get the worst gas mileage at 50 mph, I get 14 at 50 mph, 17 mpg at 45, about 17 mph at 55, and 20 mpg at 65.
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reggiecab2000
i am not denying that the lift kit and 4.10 gears isnt affecting my gas mileage i believe you are right all i was saying was that i still have the same gas mileage and even before the lift kit and bigger tires and gears. with CAI, TB spacer, and exhaust with no lift and no aftermarket gears and stock tires i still couldnt get better than 15 mpg usually...
i just didnt see a drop in MPG after the lift and stuff either

also how bad is the 10% ethanol for my truck???
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adampaul1964
Not to be a smart ass but 4:10 rear, lift and 33"tires (32.99") and your gas mileage is the same? I would be happy. I don't have any experience with the 4.3 but 15mpg in a full size pick up isn't that bad, but I understand your frustration, I usually average 15-16 in my crew cab (5.3) but that's with a slightly heavy foot, if I work at it I can get 18. But I don't work at it that hard, I drive a truck because I like it!
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P
adampaul1964 said:
Not to be a smart ass but 4:10 rear, lift and 33"tires (32.99") and your gas mileage is the same? I would be happy. I don't have any experience with the 4.3 but 15mpg in a full size pick up isn't that bad, but I understand your frustration, I usually average 15-16 in my crew cab (5.3) but that's with a slightly heavy foot, if I work at it I can get 18. But I don't work at it that hard, I drive a truck because I like it!
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I have to say I agree on this. I think that with the combination of the 4.3 and the lift and big tires, that's probably about as good as it will get. As to why there was no drop when you lifted it, I have no idea. On my avalanche I seem to be averaging between 15-16 MPG - that with the 5.3 engine, but the 4:10 gears too. On my '01 Silverado I was able to get about 24 MPG on the highway, but that was with a regular cab truck, a performance tune to dial in efficiency, and the 3.42 gears.
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reggiecab2000
well the only time i get 15 mpg is on the highway when i go home for the weekend to san antonio and ill cruise at 65 all the way from corpus, a good 150 miles. other than that im usually around 13 mpg :(

so is ethanol even good for my engine?
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2
If the truck is driven regularly it won't be affected. As long as the fuel is turned over every month or so you shouldn't have any trouble. If you only drive occasionally, I would use an ethanol stabilizer and/or Seafoam.
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sstoner911
reggiecab2000 said:
well the only time i get 15 mpg is on the highway when i go home for the weekend to san antonio and ill cruise at 65 all the way from corpus, a good 150 miles. other than that im usually around 13 mpg :(

so is ethanol even good for my engine?
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I have 4.11 gears with the 4.8 Vortex. I am running 22" wheels. In the city I get 14MPG.....freeway 80-85MPH with cruise control 17MPG
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LURCH
Hopefully when mine gets broken in it will do a little better, now I'm getting 12 to 13 but its only got 250 miles on it. 5.3 auto with 3.42's.
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V
We just sold our 98 4 door blazer and it had 145k on the clock and was still getting 16-17 on the hwy, nothing was EVER done to that thing except normal upkeep. The 4.10 gears surely arent helping, and most likely those rims and tires have more rolling resistence then the factory tires that are much more narrow. I would ensure that everything is correctly siezed to the computer with your hypertech (tires size & gears). Get rid of the TB spacer, it serves no purpose on your truck. Also what kind of plugs did you put back in it, many of the so called ECO plugs dont do anything thing to a vortech motor except make them run worse, go to the factory OEM plugs. How big of diameter is your exhaust, it could be TOO big and this would hurt it as well.
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reggiecab2000
I dont do any of those eco plugs i stick with AC delco like my father taught me too...
and i know my tires are bigger than stock which was (255/75R16) i believe, but then i see 275/60R20 coming stock on most dodge 1500's,and 275/55R20 stock on most new chevy 1500's
so it hardly looks like my tires are bigger than most... but im sure those trucks are designed to work with those tires as well
I dont know my exhaust diameter i went from dual exhaust out the rear to dual turn downs about 6 inches after the muffler about a year ago, and no mileage difference.
How would bigger exhaust be worse? from what i know the faster the exhaust gets out the better your engine breathes. i didnt know there could be a too big?
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