2019 Silverado fuel range not reading the same as the fuel gauge.

Weekend101 · November 29, 2022

My 2019 Silverado RST crew cab 4WD when it was new on a full tank the computer for range would show 425 to 435 miles. This last few weeks it has drop to 365 miles. This week the range show 312 miles with the tank full. Truck has just over 42586 miles on it. Best mileage is 22 per gallon. Put new tires on at 1000 miles ago and drop to 18 miles per gallon. I can live with that mileage for the tires I went too. Just return from a ELK hunt and average 18 miles per gallon over 1500 miles round trip. Took it to a Chevy dealer no codes show up. Couldn't find anything wrong. I was told it was the winter gas and how I have been driving the truck. Any ideas or anyone else has had this happen?

SeekAndDestroy · November 30, 2022

8 hours ago, Weekend101 said:I was told it was the winter gas and how I have been driving the truck. Any ideas or anyone else has had this happen?

Winter gas will lower economy. My truck uses about 20% more fuel in winter because of the gas blend and warmup time. The truck will “learn” driving habits and adjust the DIC accordingly. Heavier tires will lower fuel mileage.

Transient · November 30, 2022

It's not just the winter gas and bigger tires. Winter has cooler air. Cooler air is more sense. The truck is programmed to run a mixture of air to fuel of 14.7 to 1. Therefore, as the air temp is cooler the truck is programmed to utilize more fuel in order to prevent it from running lean. Go to warmer climate, like Arizona or Southern California and you'll see better mpg.

newdude · November 30, 2022

On 11/29/2022 at 10:09 AM, Weekend101 said:

My 2019 Silverado RST crew cab 4WD when it was new on a full tank the computer for range would show 425 to 435 miles. This last few weeks it has drop to 365 miles. This week the range show 312 miles with the tank full. Truck has just over 42586 miles on it. Best mileage is 22 per gallon. Put new tires on at 1000 miles ago and drop to 18 miles per gallon. I can live with that mileage for the tires I went too. Just return from a ELK hunt and average 18 miles per gallon over 1500 miles round trip. Took it to a Chevy dealer no codes show up. Couldn't find anything wrong. I was told it was the winter gas and how I have been driving the truck. Any ideas or anyone else has had this happen?

Sounds normal to me. Have you been using remote start a lot? Idling to warm the engine/cabin for long periods of time? Are your new tires stock size? AT or MT tread? Oversized?

Edited November 30, 2022 by newdude

Weekend101 · November 30, 2022

No idling, tires are 285/65R18 AT. With these tires last month on 1500 to 1800 miles around trip the truck did 18 miles per gallon. That I am happy with. What has me confuse is when filling the tank up it would always show 425 to 435 miles range. But now it is showing 312 miles range and I haven't even moved the truck. In my books a full tank should show the same with each fill up. The faster the fuel gauge goes down the worse mileage one is getting. But to lose over a hundred miles on a fill up seems odd. This is what the computer range is showing. Fuel gauged is on full. Going to try a fuel additive and maybe fuel system cleaner. Also going to check my mileage by hand and see if the computer range is off.

calgator73 · December 6, 2022

On 11/30/2022 at 1:34 PM, Weekend101 said:

No idling, tires are 285/65R18 AT. With these tires last month on 1500 to 1800 miles around trip the truck did 18 miles per gallon. That I am happy with. What has me confuse is when filling the tank up it would always show 425 to 435 miles range. But now it is showing 312 miles range and I haven't even moved the truck. In my books a full tank should show the same with each fill up. The faster the fuel gauge goes down the worse mileage one is getting. But to lose over a hundred miles on a fill up seems odd. This is what the computer range is showing. Fuel gauged is on full. Going to try a fuel additive and maybe fuel system cleaner. Also going to check my mileage by hand and see if the computer range is off.

I think it calculates that range off of the last 50 mile average. That 312/22=14.2mpg. Seems reasonable considering your hwy fuel economy is 18.