M.P.G. question

[Jared Jackson]

I tend to use MPG as a marker for my engine being healthy. I never expect my truck to get good gas mileage. But, as long as it's getting the same crappy gas mileage, I know everything is running right.

 

[88 one ton]

Only thing my truck doesn't pass is a gas station...
Checking in with 8mg 454 efi 4l80e 4:10 gears 88 dually

 

[RichLo]

Only thing my truck doesn't pass is a gas station...
Checking in with 8mg 454 efi 4l80e 4:10 gears 88 dually

yea that would suck it down!

 

[L31MaxExpress]

Hey guys! Quick question. I went to the gas station tonight and $70 later she was full! I ran the math and I got 13 mpg... ouch. It was almost all city driving though but with news plugs and wires I figured it would be closer to the 15 that the EPA suggested. Unless is getting 13 normal or do I need to tune it up a little more? Auto trans (sadly) with the 4.3

4.3 was never known for fuel mileage even in a S10 or M-van. In the heavier trucks and fullsize vans the 305 and 350 get better mileage. Around Dallas/Fort Worth I am averaging about 15 mpg in my cammed 8.1/4l80E/3.42 geared 1999 Tahoe. Strictly city driving it is getting about 11-12 mpg. It takes roughly X amout of fuel to move Y amount of weight and the smaller engines have to work harder to move the weight from a stop and get up to speed. Driving style will help the most. The less you push the brake pedal the better your mileage will be. Anticipating the road ahead and coasting to bleed off speed help MPG tremendously.

 

[df2x4]

4.3 was never known for fuel mileage even in a S10 or M-van.

I must have the most efficient Vortec 4.3 in the world then... Before I did the 4L80E swap I was averaging well over 20MPG every fill up in my red C1500. The bigger transmission has definitely knocked that down a peg or two, though.

 

[L31MaxExpress]

I must have the most efficient Vortec 4.3 in the world then... Before I did the 4L80E swap I was averaging well over 20MPG every fill up in my red C1500. The bigger transmission has definitely knocked that down a peg or two, though.

His is not Vortec though. It is the underpowered TBI variety.

My fuel mileage did not change from the 60E to 85E swap. Still the same 17-18 mpg it got before. 3.42 to 3.73 swap it stayed the same. Swapping to the 1-ton suspension with the 5.13 geared 10.5" knocked it down nearly 1 mpg highway but doing that swap gained 6" of height and about 400 lbs.

 

[df2x4]

His is not Vortec though. It is the underpowered TBI variety.

Gotcha. I was on mobile so I couldn't see his signature with the truck info.

 

[Bodageta1995]

95 K1500, no lift 305/70R16 Toyo Mudgrips, Automatic, Extended Cab. I get 12-13mpg and most of my mileage is highway. Best ever was a little over 13, usually closer to 12. I've recently replaced every electrical engine component including plugs, wires, coil, EGR control etc and 2 new GM fuel injectors, O2 sensor. My mileage stayed the same. The only thing that I have seen is that I was getting more like 10-11mpg when I first bought the truck a year ago and then I put more air in the tires and saw about a 2mpg increase. I have the receipt where the previous owner replaced the cat convertor no long ago. I had bought this truck counting on 15-16mpg. The search continues. I will say it is the weakest vehicle I've ever owned ever. Weaker than my 1983 2.8 liter (i think) V6 4wd Chevy Blazer I had in the late 80s. I haven't checked the timing and need to. Mabye it's just weak, or bad power to weight ratio, or maybe the tires are too heavy and big. It's crazy weak but doesn't burn oil at all. Anyhow, your mileage seems not so far from mine and yes gas prices are going up. Taxed heavey in Georgia too. Georgia snuck in a 25, or 29 forget, cent/gallon increase a couple years back when prices for gas were rock bottom. Go to the Great State of Alabama and you can see what gas should cost. There are good people in Alabama by the way, or so Skynard used to say. I like Auburn myself.

 

[Jack Schneider]

95 K1500, no lift 305/70R16 Toyo Mudgrips, Automatic, Extended Cab. I get 12-13mpg and most of my mileage is highway. Best ever was a little over 13, usually closer to 12. I've recently replaced every electrical engine component including plugs, wires, coil, EGR control etc and 2 new GM fuel injectors, O2 sensor. My mileage stayed the same. The only thing that I have seen is that I was getting more like 10-11mpg when I first bought the truck a year ago and then I put more air in the tires and saw about a 2mpg increase. I have the receipt where the previous owner replaced the cat convertor no long ago. I had bought this truck counting on 15-16mpg. The search continues. I will say it is the weakest vehicle I've ever owned ever. Weaker than my 1983 2.8 liter (i think) V6 4wd Chevy Blazer I had in the late 80s. I haven't checked the timing and need to. Mabye it's just weak, or bad power to weight ratio, or maybe the tires are too heavy and big. It's crazy weak but doesn't burn oil at all. Anyhow, your mileage seems not so far from mine and yes gas prices are going up. Taxed heavey in Georgia too. Georgia snuck in a 25, or 29 forget, cent/gallon increase a couple years back when prices for gas were rock bottom. Go to the Great State of Alabama and you can see what gas should cost. There are good people in Alabama by the way, or so Skynard used to say. I like Auburn myself.

As stated above, TBIs are very underpowered lol but they do have great torque. I have 275 tires right now so I’m surprised that yours isn’t worse! I’m thinking about putting a K&N filter in it and see if that helps. Maybe my newish STP filter sucks

 

[jsfrmsj]

I took out the 160 thermostat and put the 195 degree one back in and I'm back up to 14 mpg (from 11.5mpg). That was very mixed driving as well, mountain pass, city, and highway.

Its well documented that the lower temp thermostats kill mpgs, so if you have one you might want to go back to factory specs.