GMC 1500 V6 gas mileage

11 replies to this topic
  • Hondapwns

Posted May 24, 2008 - 03:07 PM


I had started a thread where I was talking about what kind of truck I was saving for. I origonaly had my eyes set on a 88-97 Serria with the V8. Now with gas hitting 4.00 a gallon, thats out of the question. How much better mileage would a 1500 with the 4.3 V6 get vs the 5.7 V8?

  • cardiffchris

Posted May 24, 2008 - 03:15 PM


I had a 1990 s10 with the Fuel Injected 4.3 & automatic, and my mile per gallon ranged from 15 to 18.

I dont know how you can get 20 plus out of a full size truck.

I guess i'm a leadfoot.

  • zz3gmc

Posted May 24, 2008 - 03:54 PM


My 91 GMC 1500 4.3l, would get 20-24 on the hiway as long as I was taking it easy and it was relatively flat. In 96, I put a 345hp GM crate motor in it and got a best of 19mpg, again taking it easy, in 5th gear with the cruise on. My 05 GMC 1500 5.3 with 3.73 gears has hit about 21-22 at best. Both trucks are regular cab,2wd, short beds. My 98 G2500 van with a 5.7 hit 19mpg at best. I typically get about 14-16 out of the van.

  • Chevy_Cowboy

Posted May 24, 2008 - 05:01 PM


The 4.3 is a great motor, but it doesnt get great mileage in the full size trucks... in most cases the 5.7 will get the same mileage.

If ya get a smokin good deal on a 4.3 silverado buy it... but don't buy one thinking you're gonna get better mileage because you'll be disappointed.

  • davidfloyd

Posted May 24, 2008 - 05:38 PM


Agreed. I owned a 4.3 V6 Silverado single cab with a 5-speed manual transmission as well. I commuted with it for years and the BEST I could get out of it was close to 18 mpg in the very BEST conditions and being very easy on it. Good motor, good power, but the 5.7L V8 in the Silverado will get the same MPG. The best MPG you're going to get out of a truck these days is a Ford Ranger/Mazda (same truck) and there you'll be getting into the mid 20's in best conditions with a 4-cylinder and manual. That may be too small of a truck for you though - unfortunately it doesn't seem like you can have the mileage into the 20's with a fullsize truck.

  • Bigmutha

Posted May 24, 2008 - 07:21 PM


I just sold my 2007 Silverado classic today. 4.3 V6 5 speed manual. Sticker said 23 mpg on the highway.... No way. The best I ever did was 19mpg. The small V8 automatics are around there.

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  • zz3gmc

Posted May 24, 2008 - 08:02 PM


Not doubting anyone, but Ive done it. It wasnt a common occurance. My brother also has a 91 1500 with a 4.3 5spd and he has the same results. His has over 200K and still runs great. His 90 454SS gets around 14mpg with a OD conversion.

  • adam728

Posted May 25, 2008 - 05:19 AM


Had a 92 K1500, long bed reg cab, 4.3L, auto. 17 mpg if I was very nice to it, 15 mpg under "normal" driving. The truck was in the family since new, and that's the numbers it always saw.

I really hated it when my dad got a 99 K2500 WT with the Vortec 350. Truck was much heavier than mine, had a ton more power, and usually would get 1-2 mpg better than mine!

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  • enduro4231

Posted May 25, 2008 - 06:22 AM


'89 K1500, Reg. cab longbed auto. 4.3L. I got 15 highway 12 city.

  • Matt 193

Posted May 25, 2008 - 11:21 AM


From everything I've heard the v-6 makes the same or less mpg then the v-8 because it is slightly under powered and it just gets more noticable once you start to use it for working or hauling.

  • Hondapwns

Posted May 25, 2008 - 11:33 AM


well, thats dissapointing, but it makes the V8 seem like the better option.

I know its gonna cost a fortune in gas, but I really need the bedspace

  • WR250G

Posted May 25, 2008 - 05:55 PM


When the national speed limit was 55mph in the early 90's my 91 fullsize, shortbed, 3.42 geared, 5spd chevy 4.3 would pull down 24mpg during an often traveled 5 hour trip. It had a\c and cruise for options and I would cruise up to 65mph on occasion. I still have the truck and now going up to my campsite which is 2.5 hours away, I got 21mpg at around 65-70mph 2 weeks ago. I also owned a 92 5.7 sport with 3.42's and a 5spd and got 19mpg on the highway. It was fully loaded but had headers and exhaust as well as a few minor intake mods. As long as the 5spd trucks had a somewhat easy gear, you could get decent mileage. I always believed the GM automatics get better mileage than most for whatever reason.
I felt the 5.7 makes better power(of course) than the 4.3 but the v6 isn't too bad of a daily driver.


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