I have a 07 4.8 regular cab 4x2. It is leveled with stock wheels and tires. The best mpg I've ever got was 15.5. I bought the truck 3 months ago with 133k miles. I've changed the plugs, wires, added intake and exhaust. Is 15.5 as good as it gets for this truck? That is driving without ac, in the highway with a light foot. This is my first truck I was expecting 16 city 19 to 20 on the highway.

 

I have a 2013 extended cab 4x2 with the 4.8 and I get about 17 highway and about 13 in the city.

 

https://www.fueleconomy.gov/feg/Find...22880&id=17026


my 2000 sierra 1500 4x4 4.8L with 5 speed manual would get 16mpg around town and 22mpg hwy...imperial gallon

installing a tonneau cover will get 1mpg increase...that's why the hybrid trucks come with them from factory.

 

What is your rear end gear ratio? . Also, how many inches higher is the front of the truck after the leveling was done?

 

Idr my gear ratio. Nothing quick, it's a dog on the low end. Front end is is just a hair over leveled with the back

 

You might phone in to a GM parts counter with your VIN and ask what the gear ratio is on the differential. That way you can compare apples to apples with other trucks.

SD

 

Better yet. There is a VIN decoder in the tool section in the Tool section at the top of this page. Just get your VIN number off the truck and type it in.

SD

 

That's the mileage I get with my 2009 1500 4 X 4 with a 5.3 V-8 with 3.73 gears and I think that is bad, but I only have 45K miles on it and have a cap over the bed. Mine is pretty quick off the line, so you probably have 3.42 gears at best. Good luck with that one. Maybe your engine is getting tired. If you don't figure it out, you might have to do a compression check to see what shape the engine is in. 69impalaconvharv