Wildly different EPA gas mileage figures. 5.7L Tahoe.

[Scoobey]

It's curious, but the EPA mpg ratings shown for the 2000 Z71 Tahoe on Edmunds.com are 14/18, but the official EPA site says they're 11/15. The EPA also says it's adjusted its older ratings to match what I guess is a different method used to calculate the newer ones -- but that's a pretty big difference for that explanation, in my mind.

EPA
Edmunds

And somewhere else I heard the Tahoe gets 15/20 (though maybe that's a smaller engine than the 5.7).

What do folks REALLY get with their 5.7s? Any ideas on the differing EPA figs?

 

[Paul Greathouse]

The model year (2000) may be what is causing the confusion for you. I think that was the year they swapped motors in mid year (5.7 to 5.3). The 5.3 will get 15/20 but I have never heard of the 5.7 getting that good.

I live in southern Louisiana, the land is as flat as it gets down here, which should produce the best gas mileage figures. My 2dr 4wd 95' with 100,000 miles and a fresh tuneup gets 14mpg city/hwy combined. Everything on it is stock, no modifications as of yet. I have only had it a few weeks so I haven't taken any long trips in it to check strickly Hwy mileage. but I would suspect 16 would be about the best. Most people don't do strictly hwy driving anyway so the 14mpg figure is probably the closest your going to get to real world, everyday driving. The Vortecs came out in 96', they have a little more power and they might get slightly better mileage. I am running 265/75/16 Uniroyal Larado all terrains on the Tahoe with no lift kit, larger tires and a lift may increase fuel consumption.

Just a side note, before purchasing the Tahoe, I drove a 95' GMC 3/4 ton with a 5.7 and a 5 speed standard shift for the last 12 years. I did take some non-loaded road trips in it up to central Mississippi. It was all mostly flat interstate and the best I got in it was 15mpg. Thats a 2wd with hwy tread tires.

I have heard of 5.7's in cars with the higher gear ratio rear ends getting 20mpg on the hwy but I have never heard of those same results in a truck or SUV.

Hopefully some other folks will comment on their mileage. I would like to hear about more real world figures myself.

 

[Scoobey]

Model year change

Thanks for replying! I've taken the model year change into account -- the 2000 Z71 was the last of the old body style and engine, and the rest of the 2000s were the new one. There's a good thread on mileage figures here, but many of the entries don't distinguish between different motor sizes, nor between gear ratios. I could be OK with 15-20 mpg but I'm concerned that with the 5.7 (albeit Vortec) and the "off road" Z71 package (does that include the lower gearing and therefore worse mileage?), I could be below 15 -- which would really bite.

Like you, I'd love more responses on people's mileage, especially including which motor and which gear ratio!

 

[Paul Greathouse]

I had forgot to mention earlier mine has 3:73 gear ratio. Even with the Z71 package the 2000 model probably has 3:73 also. The Z71 package usually includes better skid plates and better suspension.

 

[Hardwarz]

I have a 4x4, 4 door, 5.7l 1999 tahoe.

I get between 10-15 mpg.

On the highway, when I draft behind a semi, and go 55mph, I've gotten 20mpg.

Hardwarz

 

[96ProCompTahoe]

with the lift on mine and not yet regeared i get almost 12mpg mixed. almost 14 on mostly highway.

i got around 16-17 mixed before the lift.

probably could have/had improved both if i would have driven it for mileage

 

[General Stalin]

I have a 1995 4dr Tahoe LS (Throttle Body Injection, not Vortec) 5.7L 350 cid and just the other day I refilled my tanks finishing a mileage test, and I got 14.6 mpg (O_O) pretty awesome in my opinion. I took it pretty easy, though. That was also when I was past due for an oil change. I just changed my oil the other day and am about to go on a trip this weekend, so I will do another test. Last time I did a mileage test I got 13.8 mpg if I remember correctly. Just to clarify: I have stock rearend and no lift or anything. My tires are also in really bad shape so I'm sure I could get better mileage, but I just haven't had the money to cough up on new tires.

 

[ColaCanyon]

I have a 2000 Tahoe Limited (OBS 140,000 miles) and I average between 16-17 mpg with a mix between city and highway driving. I haven't taken it on any trips so I'm not sure what it gets on just highway.

 

[GMCYukalade]

I just went to Boaz Alabama on a Youth Revival trip, i took my yukon 99 5.7 4x4 - 20in wheels 255/75/20 - Had trouble on the way there, cyl 5 miss-fire, cyl 6 missfire - i got around 400 miles to a full tank of fuel, and thats going on I-40 from NC, so you go thru what they call the Gourge.. its all up hill at 70+MPH then you hit all that good flat land from there after - so what ever that averages out to..

 

[footinSD]

99 Tahoe 4-door:
City - 12 (10% ethanol blend), 13 (regular 87 octane)
Highway - 15 (10% ethanol blend), 16.5 (regular 87 octane)

This is driving 80 mph on highway and have obtained these numbers consistently for the past 3 years. I'll be impressed if you get better than 17 with the 5.7.

 

[bran's99]

Take back what I said. I'm getting a 15mpg mix.

 

[bill mitchell]

I have a 1995 2 door with 3:73 stock rear and 5.7 engine. On a 600 mile interstate trip at 75 MPH I got 16 MPG. Local driving, very little city, I get about 14.5 MPG. I tried one of those $69 chips and got better perdormance but the gas milage has stayed the same. I bought the Tahoe a couple months ago so I don't know when it was last tuned. It runs good at 83,000 miles.

 

[lesterl]

I have gotten 17mpg Hwy on my 95 2wd, it has been lowered and is the TBI variant 350. It needs a front end alignment, has stock 15" new tires. I plan on putting it back to stock ride height soon as I can find some stock coils and pickup some control arm bushings.

 

[jpoldschool]

gas mileage

I have a '98 2 door. Before i tinkered with it the mileage was 13/16. After dual exhaust flowmasters, hypertech program change, and replacing the clutch fan with electrics the mileage is now 16/20. I kinda have to keep my foot out of it to do that, but it's much nicer to drive.