MPG Pt.1

[Irish_Alley]

whats wrong with 15 mpg?

[Stewart G Griffin]

whats wrong with 15 mpg?

Because even the 350 and the 305 with 2 barrel got better than that----up to 17 and half sometimes.

This is the "new" 4.3 v-6 remember?

[Stewart G Griffin]

250.0 miles/ 16.362 gallons = 15.28 mpg

$1.899 per gallon regular.  $31.07 to fillup at Pep-Up.

Still working on carb tuning.  i think this engine is tired and needs a rebuild.

[Greybeard]

whats wrong with 15 mpg?

Because even the 350 and the 305 with 2 barrel got better than that----up to 17 and half sometimes.

This is the "new" 4.3 v-6 remember?

I think you answered your own wondering here...

[Stewart G Griffin]

253.0 miles / 15.738 gallons = 16.07 mpg

$1.999 per gallon regular at Sunoco, $31.46 to fillup

A little better but still not quite there.  Adjusted the choke pulloff.

i got the idle mix screws about as lean as i can go.   i think this engine is tired, worn-out and needs to be rebuilt. It's 30 yrs old after all.

But i can't switch for a few months due to time/money etc.

[Irish_Alley]

also stew you will see a better mpg once they switch back to the summer blend. i know my imp is ussaly around 23 with the winter and 28 summer or something like that

[Stewart G Griffin]

also stew you will see a better mpg once they switch back to the summer blend. i know my imp is ussaly around 23 with the winter and 28 summer or something like that

Hopefully.

[Greybeard]

Bump your tires air pressure up a bit more. Running full sidewall pressure makes for a rougher ride however and possibly over-inflation too.

[Stewart G Griffin]

265.7 miles / 16.826 gallons = 15.79 mpg

$1.959 per gallon regular at Mobil.  $32.96 to fillup

This is just sad.  i don't think this engine was very well maintained.  It still runs ok though.

[Irish_Alley]

stew think about the power:weight/drag ratio. theres a reason why my mpgs went up when i put a bigger motor in my crew cab, i went from a gas 350 to a diesel 360. im making more power at the lower rpms to get up and moving and my power band is 160 hp at 2500 400 ft lbs at 1600. now these numbers are stock and for a new motor. but i should be around there. im cruising around 1800 rpms at 62 mph she seams happy just to cruise with little effort there. nothing after the engine has changed except i gained a few hundred pounds (cummins is about 1100 lbs). im not sure if its cause im not past my hp band or if its im cruising at my tq band. want to say its my tq band, but shes happy right there. maybe you need to find your tq band and see where that will put you. remember after 55 youre fighting wind more than your weight and tire drag.

[Greybeard]

I always heard that a stock 350 likes about 2200 rpm cruising. Can't say how accurate that is. I think 15mpg for a old 350 engine is pretty good. If you want better disconnect the four barrel side and only run two barrels. Or swap a small two barrel onto it. There is only so much that can be done realistically though. These engines are caveman parts compared to today's engines. For the best mileage you need to open the bottom, install a windage tray and wiper setup, remove the water pump drive and make it electric, add electric fans, put synth in the transmission and rear end, buy hard compound tires, get a really good ignition system with multi-spark box, remove as much weight as possible, cover the bed or remove the tailgate, etc. Each by themselves does little to nothing, added together it might get you another 1.5 mpg. Of course, the cost will blow that savings out of the water.... 

[AZ87V10]

You're forgetting that he swapped the 350 out of his truck and put a 4.3 v6 in its place. I used to get around 16 to 17 mpg out of my 4.3 but that was in my S-10's! So your truck getting 15 is actually pretty good considering there's more weight to move around! I tend to get around 13 mpg out of my 350, maybe 14 if I drive it like an old grandma! These trucks were never built for efficiency, they were designed to work and haul loads! As much as we love them, they have the aerodynamics of a brick on wheels! Lol!

[Irish_Alley]

if it makes you feel any better my 02 chevy with a 4.8 ½ton only gets 16

[zieg85]

When gas was 100% I got 15-16 with my 454 4 speed with a 3.21 rear end.  That was when the speed limit was 55, I drove as if I had an egg between my go pedal and foot.  The 4.3L that was in my 86 got maybe 14 on the trip home from when I purchased it.  It ran good but it seemed like I had to really mash the pedal to keep it at speed, that was a 3 speed manual with a 2.73.  My 4.1L is getting 15-17 on the highway with the same trans and rear end in my 84 but pushing 70mph.  That truck has a topper and 70 series tires

[Tazman]

I find this talk about mpg very interesting now that I just accepted a job offer in downtown Phoenix which is 30 miles from my house and gas just got back to 2 bucks here. Yet I love driving my truck (brick) so I will pay for the gas while doing what I can to save it. I pay very close attention to the shift points while watching the tach. When I can go 65 mph while doing 1900 on the tach I think I am doing okay at saving money on gas.