Im looking into getting a 00+ 5.3 4x4 tahoe or suburban here pretty soon. But i want to improve on the gas milage as much as possible. Right now i have a 99 4.0 jeep cherokee 4x4 and get 17mpg on a GOOD day usualy around 16.5 or so. If i get a new vehicle i dont want to go down.

So my question here is what are the things i can do to improve the gas milage besides keeping off the gas ? How much more can i get from a k&n FIPK, cat back exhaust (maybe new cats?), TB, TB spacer?, pcm tune?

 

A cat-back system will get your biggest improvement. The intake,MAF, and throttle body mods put together won't make as much difference as just the cat-back. Also, the factory cats flow surprisingly well. At 120kmiles I replaced mine with high flow units and couldn't tell any difference. I'm not sure how much you will get from tuning, because I haven't tried to optimize an 87 octane tune. I'm sure if your worried about mileage you don't want to have to pay extra for premium fuel.

 

ill keep it at 87

 

it's a V8, you won't get good gas mileage. I get bad mileage with my 4.8, but I do kinda have a leadfoot from what I've heard I'd stay away from throttle body spacers.

 

Take the lead out of your shoes

 

So true, I don't think there is such a thing as a 5000 pound v8 beast with good gas mileage. Also, from personal experience, the products that advertise increased gas mileage (i.e. intake and exhaust) decreased my gas mileage. Sure they'll increase it if you have a clogged filter or exhaust and then replace it, but this isn't the case on a new vehicle. This is without a heavy foot too. A custom tune will increase it slightly, so it'll eventually pay for itself. Just my thoughts.

 

My wife went from a 2000 Jeep Cherokee to a 2004 Tahoe, and was also
worried about MPG. She is very happy with her new ride, and impressed with
the MPG. You will never look back at the Cherokee.

 

before cat back i got about 12.5 mpg around town, now i get 13.5-14mpg. Considering my truck and what it does im quite hapy with that.

 

87 oct tune (Nelson) = .5 to 1 mpg increase
93 oct tune = 1 to 2 mpg increase

Air intake = 1 to 1.5 mpg
Cat-Back = .5 to 1 mpg

Electric fans = 1 to 2 mpg

Synthetic engine oil and sythetic trans fluid = .5 to 1 mpg

2-4 psi higher than recommended tire pressure .5 to .75 mpg

Lower rolling resistance tires such as a narrower tire and/or a street tread tire instead of an mud/snow tire == 1 to 2 mpg

VR velocity stack = 1 to 1.5 mpg (this is a what someone just reported on their Yukon) https://ls1tech.com/forums/showthread.php?t=216214


MPG results of my recent fishing trip.
Kearny to Cape May, NJ , 170mls each way.
Road used GSP
Cruise control at 68-69 MPH, A/C on.
200 lbs of Tuna (bluefin) in the bed on the way back

Truck:
2000 Sierra 5.3l 4x4 ECSB
275/60 R20 michelin LTX M/S (mud/snow tires) (33" overall diam) @ 35 PSI
Uncovered bed with gate closed

Mods:
87 Nelson Tune w/All TM removed
Amsoil synthetic engine oil and trans fluid
LT1 electric fans



MPG AVG == 17.46


=Dave

 

i average 18 mpg on the highway. i average around 12 to 13 intown. i weigh in at 5126 with everything in her.