The ongoing global microchip shortage has resulted in lost production and reduced features for a variety of GM vehicles, including the removal of automatic engine stop-start from certain 2021 Chevy Silverado 1500 models. Now, we’re taking a closer look at the fuel economy numbers for 2021 Chevy Silverado 1500 models no longer equipped with automatic engine stop-start.
For those readers who may be unaware, automatic engine stop-start was designed to reduce emissions and improve fuel economy by automatically turning the engine off when the vehicle is stopped, such as in heavy traffic or at a stop light. The system will then restart the engine when the driver removes their foot from the brake, allowing it to continue forward.
According to General Motors, most 2021 Chevy Silverado 1500 models built after June 7th, 2021 with a V8 engine and 10-speed automatic transmission will not be equipped with automatic engine stop-start. That includes RST, LTZ, and High Country trim levels equipped with the naturally aspirated 6.2L V8 L87, plus LT Trail Boss models equipped with either the naturally aspirated 5.3L V8 L84 or the naturally aspirated 6.2L V8 L87.
To note, 2021 Chevy Silverado 1500 models not equipped with automatic engine stop-start may still be equipped with Dynamic Fuel Management, which automatically shuts down engine cylinders under light load to maximize fuel economy. That said, the chip shortage has also resulted in some 2021 Chevy Silverado 1500 models being built without Active Fuel Management and Dynamic Fuel Management, with GM offering a $50 credit for those models which normally would offer the systems.
With that covered, check out the complete fuel economy breakdown below:
| Trim Level | Drivetrain | Engine | Transmission | Auto Stop/Start | Cylinder Deactivation | City mpg | Highway mpg | Combined mpg | Effective Date |
|---|---|---|---|---|---|---|---|---|---|
| All | 2WD | Turbo 2.7L I4 L3B | 8-speed auto | Yes | AFM | 20 | 23 | 21 | Start of 2021 MY |
| All | 4WD | Turbo 2.7L I4 L3B | 8-speed auto | Yes | AFM | 19 | 22 | 20 | Start of 2021 MY |
| All | 2WD | 4.3L V6 LV3 | 6-speed auto | No | AFM | 16 | 21 | 17 | Start of 2021 MY |
| All | 4WD | 4.3L V6 LV3 | 6-speed auto | No | AFM | 15 | 20 | 17 | Start of 2021 MY |
| Custom Trail Boss | 4WD | 4.3L V6 LV3 | 6-speed auto | No | AFM | 14 | 18 | 16 | Start of 2021 MY |
| All | 2WD | 5.3L V8 L82 | 6-speed auto | No | AFM | 15 | 21 | 17 | Start of 2021 MY |
| All | 2WD | 5.3L V8 L82 FFV | 6-speed auto | No | AFM | 15 | 19 | 16 | Start of 2021 MY |
| All | 2WD | 5.3L V8 L82 | 6-speed auto | No | No | 14 | 21 | 16 | March 22, 2021 |
| All | 4WD | 5.3L V8 L82 | 6-speed auto | No | AFM | 15 | 20 | 17 | Start of 2021 MY |
| All | 4WD | 5.3L V8 L82 | 6-speed auto | No | No | 14 | 20 | 16 | March 22, 2021 |
| All | 4WD | 5.3L V8 L82 FFV | 6-speed auto | No | AFM | 14 | 18 | 16 | Start of 2021 MY |
| Custom Trail Boss | 4WD | 5.3L V6 L82 | 6-speed auto | No | AFM | 14 | 18 | 16 | Start of 2021 MY |
| Custom Trail Boss | 4WD | 5.3L V6 L82 | 6-speed auto | No | No | 13 | 18 | 15 | March 22, 2021 |
| All | 2WD | 5.3L V8 L84 | 8-speed auto | Yes | DFM | 17 | 23 | 19 | Start of 2021 MY |
| All | 2WD | 5.3L V8 L84 | 8-speed auto | Yes | No | 15 | 22 | 17 | March 22, 2021 |
| All | 4WD | 5.3L V8 L84 | 8-speed auto | Yes | DFM | 16 | 22 | 18 | Start of 2021 MY |
| All | 4WD | 5.3L V8 L84 | 8-speed auto | Yes | No | 14 | 21 | 16 | March 22, 2021 |
| All | 4WD | 5.3L V8 L84 | 10-speed auto | Yes | DFM | 16 | 22 | 19 | Start of 2021 MY |
| All | 4WD | 5.3L V8 L84 | 10-speed auto | No | DFM | 15 | 21 | 18 | June 7, 2021 |
| LT Trail Boss | 4WD | 5.3L V8 L84 | 10-speed auto | Yes | DFM | 16 | 21 | 18 | Start of 2021 MY |
| LT Trail Boss | 4WD | 5.3L V8 L84 | 10-speed auto | No | DFM | 15 | 21 | 17 | June 7, 2021 |
| All | 4WD | 6.2L V8 L87 | 10-speed auto | Yes | DFM | 16 | 21 | 18 | Start of 2021 MY |
| All | 4WD | 6.2L V8 L87 | 10-speed auto | No | DFM | 15 | 20 | 17 | June 7, 2021 |
| LT Trail Boss | 4WD | 6.2L V8 L87 | 10-speed auto | Yes | DFM | 15 | 19 | 17 | Start of 2021 MY |
| LT Trail Boss | 4WD | 6.2L V8 L87 | 10-speed auto | No | DFM | 14 | 19 | 16 | June 7, 2021 |
| All | 2WD | Turbodiesel 3.0L I6 LM2 | 10-speed auto | Yes | No | 23 | 33 | 27 | Start of 2021 MY |
| All | 4WD | Turbodiesel 3.0L I6 LM2 | 10-speed auto | Yes | No | 22 | 26 | 24 | Start of 2021 MY |
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Comments
The MPG numbers on auto stop and AFM really are irrelevant.
These systems are awarded off cycle credits from the EPA. These systems can not normally be tested accurately so they are awarded EPA off cycle credits that help the mfgs meet their regulations.
Auto stop and AFM are more about emissions than real fuel mpg.
That simply isn’t true. As a former GM propulsion system development engineer I can state that these systems are functional “on cycle”. Thus, their efficacy is determined by fuel economy testing, and their impacts are included in EPA MPG numbers. For your reference here’s what off cycle credits GM has requested: https://www.epa.gov/ve-certification/general-motors-gm-compliance-materials-light-duty-greenhouse-gas-ghg-standards. Note that there’s nothing regards AFM, DFM or stop-start.
I’m not trying to sell any of these technologies. Just letting you know that EPA MPG numbers associated with vehicles with these technologies come from actual vehicle test data.
I have over 200000 miles of driving the same routes. Many different gm vehicles. New and old. The mileage they state are incorrect.. They way the report the gas mileage ratings. Have been incorrect for years
Wow, so sorry to hear the EPA does not test for fuel economy to the exact ways that you drive personally. What a shame!
I have a2018 Silverado with the 5.3liter and 6 speed transi average 29 on the highway. Remember you are driving a truck. If you want great gas mileage buy a prius
I bought a new 2017 silverado and still get really good gas mileage. I got 41.2 mph and did not delete mph
It is on the fuel economy last 25 miles. It’s a 5.3. Just got back from Florida highest 31 mph. The stock tires get better mileage. I have heavy duty tires now. The mechanics at the chevy dealer said it has more power than others like it. Drives like a Cadillac. 4 door, plenty room for my pit bull
i call bs
The real story is my Silverado 1500 LTZ, z71, 6.2L was ordered before Thanksgiving last year. It came off the production line in February and is sitting in a lot awaiting the fuel management chip. This was a special order by name and yet there are new trucks coming off the line with chips that are not scheduled to go to anybody while I’m left on the side lines with no updates from the company despite the dealership bugging them twice a week. This is piss poor logistics from GM and I might just have to go another path. It’s sad to think they can’t fix this.
The start/stop feature on ALL cars destroys the engine. There is no oil on start up until the pump begins pressurizing the system. Does not improve fuel economy…destroys starters and is the biggest automotive flop to date.
Quit running the slick50 advertisrment. Todays modern oils are 100x better than the sludge we had in 1980
What about 2020 truck with there gas mileage. I like to know
Not sure you could have said more incorrect things in two lines. Auto start stop first off does not destroy engines, it works where oil is still fresh and fully lubricating everything, oils these days are very advanced and coat very well. Starters have been beefed up to accompany this, they can handle the task of starting multiple times a trip. Finally it has been tested numerous times by third parties and shows a 5-8% gain in city fuel mileage. Idling is one of the biggest wastes of fuel there is. Please stop spreading false information, thanks!
I agree I would be very happy if my new truck came without the stop-start system. Battery cost twice as much, hard on the starter.Just let us drive the truck!
Battery costs are off set with fuel savings…
Nope
Any math to back that up? Here, let me do some math for you…
Independent tests have shown in city driving stop start can save anywhere from 5-8% mpg. So lets say you get 16 mpg, even a modest 5% savings gets you another .8 mpg. For ease of match based on your basic answer I will use whole numbers (numbers without a decimal point). If vehicle A gets 16 mpg and vehicle B gets 17 mpg then assuming 10k miles a year and $3 a gallon at 50% city driving you are saving roughly $50 a year in gas. Batteries usually last 3-5 years so let’s just say 4 for the slow folks. Every 4 years you will need to replace a battery that is costs roughly $120 (I just bought one for the wifes CUV two weeks ago), so in that 4 years you not only cover the cost of the battery in fuel savings from start stop but also roughly another oil change.
How do you feel now?
Some people, just assume without any facts or data…
Battery for new start stop are more like $200.00
My 15 Malibu has 2 batteries and the big one is 180…
Show your work!
Why is the mileage dropping on the highway when stop/start is deleted? This feature activates under certain situations when the vehicle is completely stopped and has nothing to do with highway cruising!
They are dropping AFM so no 4 cylinder modeon hway . I wonder if they are putting standard lifter engines in as the AFM lifter are 1000$ per set
Nope, still comes with all the internals to make it work.
Look at the list more closely. Only certain engines are losing AFM/DFM. The engines I’m speaking of have stop/start deleted but still have AFM listed. There should not be a drop in highway mileage only city with this feature gone.
Adjustment to MPG has to be done yearly due to the sales rates and availability of different options, specifically options that change weight, drag or different axle ratio selections.
I just bought me a 2021 Chevy Silverado custom 2.7 4 cylinder Turbo but mine has a on off switch for if you dont want to use the automatic engine stop/start just turn it off my truck save lots of fuel Love it
Start./stop is not hard on starter or battery because they are beefed up to handle the extra cycles. There are no complaints anywhere with issue with these except if they were bad from the factory. If you don’t like just push the button if it has it or set the gear selection to manual.
I for one have no issue with it except when parking in garage. Other than that is works great. Those complaining it turns off the a/c it only does that if the temperature you set is at that temperature when you come to a stop. If your waiting long enough it will start back up or just lift foot slightly off brake and it will turn the engine back on. The people complaining about this just seem to want to complain. If you don’t like it then buy a non GM vehicle, but everyone is doing it.
Joe…I don’t know if you were paid to write that…but start/stop is the worst thing for ANY engine. Also the main point is it literally does NOTHING to increase fuel MPG
All that fuel economy stuff is BS, if I want good fuel economy I would buy a Prius. That Active fuel Management destroyed the engine on my 2008 Silverado at only 154,000 miles. My Ram 1500 without any of that crap gets the same fuel mileage as the new GM trucks.
I don’t buy that one bit. Dodge’s Hemi has notoriously been know to be behind the others on fuel consumption. The Dodge’s are heavier and guess what, later model Hemi’s have the displacement on demand. Unless you own an old Ram the newer ones have it and the older ones were worse on gas than the newer ones.
No sir, I get 16-18 mpg around town and around 23 mpg on the highway in the Ram, which is about what I was getting with the Silverado before the engine took a shit. I’m not saying that one is better than the other at all. I love driving both of them. I’m just saying that all of that fuel economy crap they are putting on is a waste.
I just bought a 2021 Silverado crew cab custom 2.7 4cylinder. The posted log is 20 city 23 highway, combined 22.
Now I have put in 2000+ miles and all I get is 18 city 19 highway.
It also increases starter sales.
I bought a 2021 silverado RST 4WD with 3.0 turbdiesel in December. 25.4 mpg new the last 2 tanks I got 29.2 and 29.4 mpg. I shut off the stop start button as soon as I start it.
My question is how about MPG on 2020 Silverado 4×4 with L 84 8 speed A/T I can see in chart that was printed on 2021 Silverado there mpg