4.8 Mileage

dalez · February 12, 2005

what kind of mileage are people getting with the 4.8 vortec and 4x4 extended cab?

thanks

kevinz92702 · February 12, 2005

Last time I calculated it, I was getting around 15 mpg. However, that is with the crappy sending unit for the fuel gauge, so I may not have understood how much gas was actually left in the tank at time of calculation. Also, my truck has a v-force muffler and k&n intake; possibly some computer programming, but I got it that way. It may need a tune up also. I think the average number is around 20-ish.

kevin

beetle · February 13, 2005

I don't have 4x4 but I averaged 21.5 mpg on a 750 round trip to Las Vegas ; includes some city driving.

1st new GMC · February 13, 2005

mines an '05 K1500 reg cab long bed W/T model. I'm averaging around 15.5 mpg. I thought I would get better than that.

Worktruck · February 13, 2005

I do allot of highway driving and I have a heavy foot. If I drive like a normal person I can get around 18 mpg. But at 75-80 mph I omly get 13-14 mpg. I think the 4.8 is to small of a motor for these big trucks. Next on will have a bigger V-8 or maybe go to one of the deisels.

kirkRHughes · February 13, 2005

Wow, must be the 4WD and the extra weight of the Extra cab, because I have a SCLB 4.8 and get 18-20 in the city. Almost always get 600 miles from a tank.

Fatboy2 · February 13, 2005

No extended cab - Tahoe with 4.8

13.5 with the cruise on @ 55mph. I am hoping it is the winter blend of fuel.

jhm · February 14, 2005

2001 4.8 4x4 ext cab. Average 14.8 mpg. That is basically rural driving, might be better on long trip, havent calculated that because 90% of my driving is rural.

MS3DALE · February 14, 2005

My '99 ext.cab 4.8 4x4 got around 16.5 back and forth to work and I could get almost 19 on the highway if I kept my foot out of it!

But to be honest the 4.8 didn't get any better mileage than the 5.3 that I have now.

sjspor · February 14, 2005

Your Rear End is going to play into this as well, a 3.42 will most likely get you another 1 or 2 mpg over a 3.73.. It's just slower off the line

jhm · February 14, 2005

I wonder if everyone is calculating the same way. When I go to fill up, I write down the present mileage and fill until the nozzle clicks off, no topping off. Next time I fill up I write down the mileage and the gallons it took. Then I subtract the first mileage from the new mileage and divide that number by the gallons. I also try to use the same pump each time just because there could be a slight incline or decline at another place causing the nozzle to click off at a different level.

Bruce03Silverado · February 15, 2005

I'm averaging 14 -16 but that's also cause I put 285/75/16 BFG AT KO's on the stock rims and that had an impact on gas mileage. Before I was averagin over 17 with the puny 245's. I also have 3.73's.

Draphty · February 15, 2005

I'm getting 16 around town, and 18 on the hiway. Magnaflow dual exhaust, K&N FIPK GEN II. Also, mine came from the factory with 4.10:1 gears. I'm very impressed with the power...but I do know the gearing is what makes it jump so hard. I saw a noticeable improvement in power with the K&N and the exhaust. I towed a U-Haul Car trailer loaded with a 73 Chevy truck from here in Texas to Alabama a few weeks ago. I figure 6000 to 6500 lbs. I got a solid 10 mpg. Handled the load with not problem.

So...basically, I have no complaints with my 4.8.