2004 4.8 sierra 1500 mileage

[72_mello_yello]

Hi my search doesnt seem to be working and need some help. Im looking at buying a 2004 4.8 litre 1500 extended cab sb truck with 3.73 gears. I have looked all over the internet but never really hear much about the 4.8 litre. I was wondering if anyone knew what kind of mileage that truck is getting on highway and if its similar to the 5.3 litre or better or worse. Thanks

 

[Molson02536]

Hi my search doesnt seem to be working and need some help. Im looking at buying a 2004 4.8 litre 1500 extended cab sb truck with 3.73 gears. I have looked all over the internet but never really hear much about the 4.8 litre. I was wondering if anyone knew what kind of mileage that truck is getting on highway and if its similar to the 5.3 litre or better or worse. Thanks

The 4.8 ltr (294 ci) was produced as a gas saving alternative to the 5.3 & 6.0. My dad's Tahoe (5k pounds) gets 18 MPG on the freeway, opposed to the 5.3 which gets 15 MPG. Wish he would let me get my dirty hands on it with the HP tuner .

With the short stroke of the 4.8 which is 3.25 this little motor will make big horse numbers. 100 horse per liter is easily possible, but remember it will be at higher rpm range and upgrading valve terrain might be needed to sustain higher rpm reliability. Remember torque will be alot lower and torque is what moves cars, but could be alot fun with 4.10s and six speed.

4.8L - The smallest-displacement LS engine (293 cu in); it uses an iron block with 3.78-inch bores and aluminum heads.

5.3L - The most common LS truck engine (327 cu in), it uses the same iron block with 3.78-inch bores as the 4.8L, but with a longer stroke , (3.62-inch)crank. Later versions equipped for Active Fuel Management. Manufactured with iron and aluminum cylinder blocks.

There was an issue of piston slap, but that was addressed in the 2002 and 2003 4.8 / 5.3 and the rest of the Vortec family engines by having higher tolerance between the piston and cylinder wall with retuning the ECM during cold engine runs.

Hope this helps and feel free to ask us any more questions about the 4.8 liter vortec.

 

[72_mello_yello]

so in other words it should be better on fuel than the 5.3 litre on the highway? Thats good to know cause that makes or breaks my deal on this truck.. thanks

 

[Molson02536]

so in other words it should be better on fuel than the 5.3 litre on the highway? Thats good to know cause that makes or breaks my deal on this truck.. thanks

Yes it's better on the highway, but it's got less HP and torque. There are simple things you can do to wake it up like tuning the exhaust system with the intake and tuning your PCM for a custom program to your preference of performance.

PCMforless is one of the better investment you can do after you tune your exhaust and intake. They can reprogram your PCM with a lifetime upgrade programs for under $200.00, unless your like me with a HP tuner just for kicks. They eliminate the torque management system and bring up the speed rating to 115-125 mph depending on the tire speed rating you have, and will in most case (95%) have a better fuel economy then stock PCM program from factory.

http://www.pcmforless.com/

Good luck and enjoy your new Sierra .

 

[72_mello_yello]

Awesome! Thanks for the info. Could I buy a power programmer and get the same results? And the truck already has cat back exhaust it looks like. If I put cold air intake and get it programmed it should be above 20 mpg on the highway then?

 

[Molson02536]

Awesome! Thanks for the info. Could I buy a power programmer and get the same results? And the truck already has cat back exhaust it looks like. If I put cold air intake and get it programmed it should be above 20 mpg on the highway then?

Cold intake is all you need and a programmer if you like here is what i am using http://www.hptuners.com/index.php, but as mentioned pcmforless will have the best program for you since there program is one of the closes Dyno tuned PCM out in the market.

The power programmers will have a set of generic perimeters that is not custom, but improved from the factory setting. The HP tuner can adjust every aspect to the PCM programs from transmission shift point's firmness and engine performance to injection pulse duration and timing. The only draw back to the HP tuner is that to really get 100% of it's capabilities, you need a Dyno machine to make finer adjustments.

I was lucky enough to work at a speed shop and played many times on the Dyno and have notes to different performance setting that i use as base line to what i would like my jimmy to do and make my own finer adjustments as the years go by or how the season is. Such as i have different setting from winter and summer setting and also i do run my engine just a little lean when there is no load such as when i am cruising or at idle to get the best economy and under a load the Air/fuel ratio drops with a longer fuel injector pulse, but it will fail the E test LOL so i need to reprogram it again before i go for the E test. At stock setting my Jimmy was getting 19MPG and with the tune I'm getting 23MPG and still hard on the skinny peddle.

Good luck and give the guy at http://www.pcmforless.com/ a call and ask them any questions you may have.