Milage for a K-body with 5.7?

Milage for a K-body with 5.7?

What kind of milage does your K-Blazer/Tahoe with the 5.7 get?
I currently have an 89 S10 Blazer (4.3-Auto-4WD) that only gets 15-19mpg.
(everything is working normally & I’ve tried a few other things-no better)

I’d like to upgrade to a fullsize 2dr K-Blazer/Tahoe made between 92-98.
I was told the 5.7 gets no less than 17mpg in the city, and the newer MPI-5.7’s get over 20 on the highway. Is this true? What was the last year of TBI?

If the milage is the same as the S10, I might as well go with the bigger body & engine?

I bought a 99 Tahoe a couple of months ago. Its a 4 dr, 4 wheel drive LS with the 5.7 vortec. I recently went on a long trip with it and got only about 15 mpg on the highway. Of course, that is probably due in part to my leadfoot, I was averaging probably about 80 mph on the interstate. I havent estimated fuel usage in city driving, but I would bet money that its well under 17 mpg. I got the specifications on the truck before I bought it and if I remember correctly it was rated 14 city and 18 highway. Sounds about right to me. Earlier model years might have better mileage though due to different engine ratings. Might get slightly beter mileage out of a 2 dr model, but I cant imagine it would be much.

I have a 1995 2dr 4wd Tahoe 5.7l TBI (I'm pretty sure it is the last year for the TBI). I am lucky to get 17mpg on the highway. City mileage? - forget about it - lucky to get 13!

I bought it new and remember being bummed-out when the '96 came out with the Vortec (MPI). If I remember right they advertised about 2 MPG more and like 50 more horsepower.

Hope it helps.

Thanks people,

I needed an honest survey. Im disappointed with the mileage from my 89S10 w/4.3. I went on a few forum boards & many S10 owners claimed figures in the mid 20’s, so I couldn’t understand why MY truck (in perfect running shape) never did better than 19. I also spoke to some fullsize owners who claimed 17-20 & didn’t think that was realistic.
Thats when I got interested in the larger/stronger vehicle.

OK, so the TBI & MPI seem to get about the same MPG? One thing good about the K-body, is that it’s not too much heavier than the S10 (those are small but heavier than they look), so the power-to-weight ratio is better with the K-body. Also, the 5.7 seems to respond better to aftermarket stuff, like headers & duals, and there are many EPA-legal products out there?
Anyone notice a mileage boost with exhaust upgrades?

I have a '96 2dr Tahoe 4x4 with the 5.7 Vortec. I get probably 10 to 11 mpg in the city, but that's probably because I have 285/75 BF Goodrich Mud-Terrains which are terrible for gas mileage. I also have a 40 Series Flowmaster 2-chamber, and that gave me maybe 1 mpg more. If you do get a Tahoe and are worried about gas miileage, you should get small tires, a flowmaster, and look into the K&N FIPK, and some headers would help out too.

Hello.
I'm knew to this forum, but I have a 1995 Tahoe 4 Dr. 4x4 with a 5.7 Liter TBI. Yes, who ever said that 95' was the last year of the TBI is correct. I get about 13-14 mpg average between city and hwy. I have the orig. size 245/70/16' (BF Goodrige) tires on it. I don't know for sure and only assuming and if someone knows for sure please correct me if I'm wrong-- if you put on a taller tire on, then what the factory, then your speedometer would register a slower speed than what your actually driving at, also since your tires are actually making a bigger circle of rotation your odameter is spinning faster and register the mile before you actually travel for a mile. But this is just me thinking, please if anyone know for sure correct me.
thank you.

Thanks for the mileage info.

If you increase the tire size, yes you do affect the speedometer to
read a bit slower, although yo ca go up to 2 sizes over before it's
noticeable. Large tires also decrease the clocked miles, not the other
way around, but again not by much.

What affects speedo & clock miles more is a rear ring & pinion ratio
swap. I had a full-size Chrysler with a super high 2.45 rear.
I swapped a better performing 2.94 from a cop car. But now Im
registering 18% more than normal. There is a radar sign on the Jersey turnpike near my home. I passed it reading 55Mph but only 47 on radar.
Im also running up more miles than reality. I have to get the correct
trans pinion to correct this soon.

Thanks for your prompt response, and info.

99 Tahoe LT 4x4 4DR w/5.7L, 74,00 miles. 14MPG almost exact every time I check it around town (which I do often, 2-3 times a month). Haven't checked Highway in a long time. I drive about 20 miles a day on the expressway, and another 20 or more around town, so I have a pretty even mix of highway and city. Figure 14MPG

Ok so my S-body 4.3, is only getting about 15/19mpg. And a K-body 5.7 on the average gets 13/18…that’s not much less. And I can probably get it higher with legal headers & duals (For some reason the 4.3 doesn’t gain any MPG with headers. 5 owners told me although they had more acceleration power, mileage was the same. And they’re much much harder to install on the S10) I guess I’ll start shopping around.

I have another post, (but nobody’s responded yet) have any of you upgraded from an S10 to the fullsize. How’d you like it? Advantages/disadvantages? I like the 2dr better, but the area behind the seat of the Tahoe looks no bigger than the same space in the S10, just wider?

I went from an 85 S10 Blazer, to a 91 2DR Jimmy, to a 95 2DR Yukon, to a 98 4DR Durango, to a 99 4DR Tahoe. My favorite truck by far was my 2DR Yukon. If you don't have passengers you need to get in the back, it is an awesome truck. But if you need to access the back seat a lot, go with the 4DR. The 2DR is better looking, but I would not give up those extra 2Drs now. They both have a sweet ride, but the 2DR in my opinion rides better in the way that it feels less "bulky" in corners and turning. I also like the barn doors except for not having a wiper, although I think the tailgate looks better. But, I often trailer boats and a snowmobile trailer, and the barn doors give you much better access to the "trunk" space. NOTE: I HATED THE EVERYTHING ABOUT THE DURANGO (5.7L) EXCEPT FOR THE LOOKS AND THE 4DRS.

my 4800# curb weight 2-dr '96 Tahoe 4WD automatic gets 15.5-16.0 mph mixed commuting. Peak mileage EVER for me was 17.2 on a long highway trip where I didn't go over 70 and probably had a tail wind :p

I tested my speedo to 62 mph indicated for a true 60 mph, and verify it every day with a GPS :D

my '90 S-10 4.3 automatic 2-dr would get about 18 mpg in the same situation

96 Tahoe 4dr 4x4 mileage:
Average of 16.5 MPG + from July 17 to present, approx 16,000 miles worth. Low point was 12 (pulling boat on 800 mile trip) High point is a touch over 18. I consider this poor mileage for me, as I have not yet modified this truck. With the proper Exhaust (Flowmaster) and K&N Filter along with a few other tweaks, and I expect to be pushing an 18 Avg with peaks @ 20. Currently at 95,000 miles.

I have a 92 Silverado X-cab with a 305 (can't wait to throw a rod so I can build a 383) that runs like a top @ 155,00 miles. This truck pulls 18+ with peaks around 22 on the flat road. It is lowered, has a tonneau cover, Flowmaster, K&N and a few other minor mods. Other than this, bone stock.

Oh yeah, I drive a ton and feel that speed limits are for the "typical" drivers...

Your S-Trucks mpg is pretty typical, but just remember any GOOD performance modification that improves overall efficiency will also improve mileage...

96 4DR 4x4, 95000

I drive to school every day (30 miles one way) in traffic both ways, so im averaging about 10-11 MPG with a flowmaster exhaust, and a drop in K&N filter. Its really pissing me off!

95 was not the last year of the throttle body injection. 98 was the last year. When they went to the new body styles in 99 is when it went to multi port injection. I have a 98 Tahoe that has a 5.7 and it has a TBI.

I believe your information is incorrect..In 1996 GM went to the SFI injection system on its 5.0,5.7 engines.
In my years at the dealer, I have never seen a 98 with a TBI

Someone may be getting lost in the terminology here, but Merlin is correct. 95 was the last year for the TBI as we know it (electronic fuel sprayer atop the seemingly normal carb manifold - not true fuel injection, but way better than a carb in terms of efficiency). In 96 the SFI replaced the TBI which still looked similar to the TBI, but one difference - fuel injectors (sorta) moved from the throttle body to a location behind the throttle body which put them downstream from the airflow. The throttle body is still on a carb-type manifold, but it is now truly a throttle body that only meters air into the system. The 99 change was to a new manifold tha looks closer to the TPI systems from the F-Bodies and C-3,4,5... This system now has actual fuel rails and individual injectors for each cylinder. I learned a few things here too as I just had my head under the hood of both my 95 and 96...

I get about 13-14 on the city and 10-11 on the highway. I know that sound backwards but thats wut I get.Doin 90 to a 100 on 35's dont help none.

i have a 95 2dr tahoe. it has the tbi and i get 13. and thats with 6" lift and 35's.

1998 2 Door Tahoe Z-71 with 3.71 Gears

12-14HWY 16-19Hwy

275/65/R16
BRIDGESTONE DUELER A/T

5.7 VORTECH

1 HEAVY FOOT