2000 Suburban K2500 MPG improvements...

dano123 · October 10, 2014

Hello,

I have a 00 Suburban 2500 4wd 6.0L with 4.10 diffs and 265/75/16 a/t tires. I am all stock and average around 10-11 mpg with mostly 2 lane highway (55-60mph) low traffic driving. I am planning to tune it up soon and was looking for any advice on ways to add mpg. I recently replaced a "rigged up" muffler(previous owner had a 90 and a Tee to convert the dual inlet to a single in/out muffler) with a magna flow dual in/single out. It runs much better, but I haven't driven the truck enough to determine any mpg increase.

Also, I would like to know what mpg others are getting on average.

8.1HD/ALLISON · October 10, 2014

Hate to say it, but with 4.10s and a 6.0 it sounds about normal to me. My buddys silverado with the same setup gets same mpg.

02suburbanZ71 · October 10, 2014

My 02 5.3 sub gets the same. I wish i had the 6.0 with 4.10's [emoji32][emoji32]. Theres really not much you can do. A tune may help. But you should- replace fuel filter, clean TB, MAF, seafoam intake, vac line, and fuel tank, take to gm for injector cleaning, put in 5w-30 synthetic. Changing your lubes to all synthetic may help. So their are ways to improve the mpg

As in tune i mean blackbear. Also new GM- coil packs, plugs wires. Make sure they are GM.

Babyhauler · October 11, 2014

My last few 1500 2wd 5.3's trucks have all seen improvement with new O2 sensors. Two were over 200K mi & one was a little under. New plugs did not help alone, but the O2 sensors added from 1 to 2 mpg to my avg. I was in neighborhoods & out of town trips about an hour away in my sales job. I kept a book manually and a phone app to record mpg. 2 of them also threw codes for knock sensors and I had new GM sensors installed. That helped one of them w mileage & power. I cant remember which one. These were well maintained, synthetic oil & max tire pressure.

I just purchased an 02 2500 4x4 4 crew (161K) a couple of weeks ago & got 9 1st tank & 7.9 2nd tank. 2nd tank was 120 miles pulling my tractor & trailer of about 9,000 lbs. It felt weak & check engine had been on. I had code checked & it was for knock sensors. Well, that explains the weakness & poor mileage. I will check & change plugs, install new O2 sensors & change knock sensors. Prob knock sensors 1st, then O2.

I have several years of riding & driving a friends 2500 & he got about 11 all the time. About 800 lbs of tools & he drove hard. Another friend gets about 11 in his for the past 100k mi. He is 4wd, exhaust & a 285 mud tires. I think you should get better mpg at those lower speeds where the 4.11's don't scream the motor. Max your tire pressure. Get to high gear briskly. RPM's kill mileage.

My GM mechanic friend said to change O2's at 80-100K miles. They may not throw a code, but they get slower. Now paying a dealership full labor and retail plus will never pay off, but I think mine were about $100. for both O2's & they were easy to change. I usually run Chevron fuel and some Techron cleaner a few times a year.

A good tune is supposed to help power & economy. I need the power pulling this trailer in traffic, so I think will get a Black Bear tune in the future. After the repairs of course. I do not think they pay for themselves in savings but make driving more fun on less fuel.

Good luck & keep us posted on what you do.

02suburbanZ71 · October 11, 2014

The blackbear tune will help pull in traffic. Just make sure you tell them you need to tow heavy loads in traffic

kstruckcountry · October 11, 2014

You will be very happy with the tune but don't expect a bit increase in economy. Economy in a 3/4 ton isn't meant to be lol.

servantsalesmen · October 11, 2014

My 04 sierra 6.0 HD with 4.10's has never averaged above 11 mpg. She's a thirsty girl lol

8.1HD/ALLISON · October 11, 2014

I gained about 1/2 mpg with BB tune.

02suburbanZ71 · October 11, 2014

^^ me too

HawkScot · October 13, 2014

I heard folks lose mileage with the BB tune, but not because the tune is not optimal for mileage but rather they are enjoying the power and their right foot is all over that go pedal... once the new wears off, most experience a gain from what I have heard..

sahls01gmc · October 14, 2014

Check out 8.1HD/ALLISON's signature....that explains how you can get better MPG's. These trucks aren't designed for economy. My truck recently got 13mpg's empty (70mph and babying the throttle, and 9mpg's pulling a 7,500lb trailer. Always been that way from day 1.

I did install a K&N FIPK right after I bought it....not sure how much it truly adds....but it does sound good! I guess you could also say I saved money in the long run by not having to replace the air filter anymore.....just recondition the K&N and it's good to go!

sahls01gmc · October 14, 2014

I heard folks lose mileage with the BB tune, but not because the tune is not optimal for mileage but rather they are enjoying the power and their right foot is all over that go pedal... once the new wears off, most experience a gain from what I have heard..

Hawkeye-08, how well do you like your truck? You have the exact setup that I am looking to someday replace my truck with. Love my truck...but just wish it was a crew cab.

HawkScot · October 14, 2014

Hawkeye-08, how well do you like your truck? You have the exact setup that I am looking to someday replace my truck with. Love my truck...but just wish it was a crew cab.

I love it, only two things I would change. I would have included the wiring for truck camper or fifth wheel, but forgot and the most important, I wish I had 4.10 gears. My current setup would benefit from a few hundred more rpms when towing so it does not have to downshift as often...