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gas mileage 5.7L


gw84
05-20-2013, 08:05 PM
'99 5.7L extended cab 4x4. What kind of gas mileage is realistic for this truck? Guy told me he'd gotten 23mpg on the highway, that sounds unrealistic to me

jdmccright
05-22-2013, 09:51 AM
I would say that is optimistic at best. A C1500 std cab is rated 17 mpg highway by EPA. Add 4wd and the extended cab weight and it drops to 16 mpg.

The only way I see of even approaching that is by driving at the lowest speed possible to be in O/D and full TC lockup (usually around 50 mph), no A/C running (or removed), tires fully inflated, no cargo, and a cool day. You might hit 20 mpg.

gw84
05-23-2013, 05:37 PM
that's what I was thinking. I found the original sales sticker in the glovebox and it is rated at 17hwy.

j cAT
05-23-2013, 07:26 PM
that's what I was thinking. I found the original sales sticker in the glovebox and it is rated at 17hwy.

If it is the 5.7L in a 1500 4X4 you should get about 17 MPG max If You are LUCKY.

If you have the 5.3L engine you can get 18-19 mpg in the warm weather with 4X4.

max speed of 70MPH ...over that the MPG drops quickly.

I just did a trip to Maryland got 18.5 MPG. 70 MPG most of the way. 2000 1500 4X4 LT ext cab....

jamesslcx
05-25-2013, 05:53 PM
When I had mine I could get about 18 max on the interstate. I changed all the fluids to synthetic, K&N air filter and 35 psi in tires. Oh yea, 5w30 oil in the crankcase. Best I could get out of it.

jdmccright
05-28-2013, 12:01 PM
If he swears by getting 23 then I'd suspect speedo/odometer error due to aftermarket tires/rims and/or he swapped to different gear ratios in the differentials.

j cAT
05-28-2013, 02:36 PM
If he swears by getting 23 then I'd suspect speedo/odometer error due to aftermarket tires/rims and/or he swapped to different gear ratios in the differentials.

my guess is the guy is bad in math.

DeltaP
05-28-2013, 04:41 PM
If he swears by getting 23 then I'd suspect speedo/odometer error due to aftermarket tires/rims and/or he swapped to different gear ratios in the differentials.
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23 MPG down a mineshaft!

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