Poor gas mileage 5.3ls1/4l60e in a 1971 c10
05-28-2014, 01:22 PM
#1
Registered User
Thread Starter
Join Date: May 2014
Posts: 5
Likes: 0
Received 0 Likes
on
0 Posts
Poor gas mileage 5.3ls1/4l60e in a 1971 c10 Now that I have my speedometer/odometer working properly thanks to ls1nova and other members on this forum. I have noticed I am only getting approximately 10 mpg in city driving. I am running 5.3ls1/4l60e combo with no catalytic converter and essentially a basic tune on the PCM as it was purchased with a wiring harness from PSI. The truck has a 3:73 rear end and 28.7 inch diameter rear tires. From what I have read it seems like I should be getting at least 15 and upto possibly 20 mpg. I have not hooked it upto the scanner yet but I was hoping for some thoughts on possible causes. By the way I have not been driving aggressively.
05-28-2014, 04:19 PM
#2
TECH Regular
iTrader: (18)
Join Date: Feb 2005
Location: brunswick, ohio
Posts: 440
Likes: 0
Received 0 Likes
on
0 Posts
I have an 02 Silverado 4x4 4l60e 373 gears, stock engine 5.3 no mods. I get 18mpg in mixed driving, 20 on the highway this truck weighs 4400 lbs.. you need to scan your tune.
05-28-2014, 09:44 PM
#3
10 mpg is almost unbelievably low, does it smell really rich? Also, how much have you driven it? How many tanks have you been through? I would run several of tanks of fuel through it and average them together since sometimes you can get more fuel in the tank at one station than at another station. Have you driven it on the highway and made sure the odometer is correct with the mile markers, or at least close since mile markers are not always super accurate. Also, yeah, verify that your tune is correct.
