GM cylinder deactivation can reduce fuel use when a V8 has more power available than the driving situation requires. In the older Active Fuel Management (AFM) system, the engine control system shuts off fuel and valve operation in four cylinders during some light-load driving, then restores all eight when more power is needed. Current Chevrolet and GMC V8 SUV listings identify Dynamic Fuel Management (DFM), but the official material cited here does not explain its cylinder-control pattern. Neither system guarantees a particular fuel saving on a given SUV or trip.
What cylinder deactivation does
A V8 can produce more power than a vehicle needs during some driving situations. Cylinder deactivation lets the engine reduce the work it is doing under lighter demand rather than operating every cylinder in the usual way all the time. The intended benefit is lower fuel use in situations where the engine has excess capacity; when the driver asks for more power, the system returns to full-cylinder operation.
As an Amazon Associate I earn from qualifying purchases.
Chevrolet’s 2011 Active Fuel Management fact sheet describes AFM as deactivating four of a V8’s eight cylinders. It says the system stops fuel delivery to those cylinders and uses a solenoid arrangement to collapse their valve lifters. With those valves not operating, the engine reduces pumping losses while the cylinders are deactivated. Chevrolet lists special lifters, a lifter oil manifold assembly and an engine control module among the system’s components.
What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
That description explains the basic principle and some AFM hardware; it is not a repair diagnosis or a complete technical specification for every GM V8. The named parts can help a reader understand terms used in AFM discussions, but their presence in a system does not establish that a particular vehicle has a failed part or needs replacement.
#1 Best Overall
- Never Let a Dead Battery Ruin Your Drive. The LISEN 4 in 1 Retractable Car Charger delivers reliable power for your entire journey. Compatible with standard 12V cigarette lighter sockets, it keeps phones, tablets, and devices charged during daily commutes, road trips, and long drives — the perfect practical gift for dads, truck drivers, and anyone who lives on the road.
- Daily Driver Essential: Always Ready When You Need It. Featuring two retractable cables ( USB C & Old iPhone Charging Cable ) that extend up to 31.5 inches and dual USB ports, this charger solves cable clutter while charging up to 4 devices simultaneously. Ideal for busy fathers, commuters, and families who want a tidy car and never worry about low battery again.
- Deliver full-speed PD fast charging for iPhone 18 Pro Max & iPhone 18 Pro Max & iPhone 18 Pro right inside your car. The built-in 45W PD USB-C port hits the peak charging speed for these latest iPhone models, juicing up your phone to 50% power in just 15 minutes while you drive.(Note: Maximum 45W PD output is available under 24V vehicle power supply. When used with standard 12V car sockets, the peak output is limited to 36W.)
- Standard 12V Power Solution: Designed as a dedicated USB power supply for charging devices. Note: Does NOT support CarPlay, Bluetooth, or data transfer. Compatible with most phones, tablets, and small electronics. This retractable charger is a core car organization tool, keeping your vehicle tidy. Not compatible with Micro-USB devices.
- Clutter-Free Tech Organization: Featuring dual USB ports and retractable cables, the LISEN 4 in 1 charger provides a clean car storage solution. Perfect for truck enthusiasts or as a thoughtful gift for drivers, it supports fast USB-C charging for devices like the iPhone 18Pro & iPhone 18 ProMax. Keep your vehicle organized while ensuring efficient power delivery for all your tech on the road.
When an AFM-equipped V8 uses fewer cylinders
AFM is described as responding to driving conditions, not as a mode a driver selects for a particular speed. A 2018 Chevrolet Silverado owner’s manual says the system may use V4 mode when less power is needed, such as while cruising at a constant vehicle speed. It also says the engine maintains full-cylinder operation when greater power is required—for example, accelerating from a stop, passing or merging onto a freeway.
Chevrolet’s 2011 fact sheet also names climbing a grade and hauling as situations that can call for the other cylinders to reactivate. These examples make the operating idea easier to understand: steady, low-demand travel can leave spare engine capacity, while a request for more power can make that capacity useful. They are not a list of fixed thresholds or a guarantee that AFM will engage at a particular speed, road grade or throttle position.
The Silverado manual is a useful plain-language explanation of AFM behavior, but it should not be read as a complete description of the control logic in every GM SUV. In particular, it does not establish how a current DFM-equipped SUV chooses cylinders.
Windows Errors? Fix Them Before They Spread
Repair common Windows errors and clear accumulated junk for a smoother, more stable PC - no reinstall needed.Free scan · no reinstallOutdated Drivers Are Slowing You Down
One free scan finds every outdated or missing driver and matches the right update for your exact hardware.Free scan · exact hardware matchRank #2
- High Quality Material: The coaster is made of environmentally friendly silicone, safe, non-toxic and odorless. Soft with toughness, easily embedded in the cup holder. Very durable, wear-resistant, long service life. High temperature resistance, can withstand 100 ℃ high temperature water cups.
- Wide Compatibility: The coaster has a diameter of 3.15 inches and a height of 1.18 inches, which is widely used in most vehicles, such as SUV, sedan, MPV, etc., as long as the size fits your car cup holder.
- Protection Function: Our car cup holder coaster has a carry handle design and a stand-up ring edge on its edge to effectively prevent food crumbs, drinks and water from leaking out and preventing the car cup holder from getting dirty.Meanwhile,Thickened design effectively prevents the cup holder from being scratched by the cup when driving on bumpy roads and eliminates the annoying thumping sound, making your journey more enjoyable.
- Easy to Use and Clean: With embedded installation, you just need to put it flat on the car cupholder. It is also very quick to remove, there is a small bump on the coaster, pinch it and you can easily remove the coaster. It is very easy to clean, rinse with water or wipe with a wet towel (be careful not to clean with sharp tools).
- 100% Satisfaction: Our products have quality assurance, if you have questions or are not satisfied after receiving the product, don't worry, please contact us as soon as possible, we provide after-sales service.
AFM and DFM are different names, and the distinction matters
Older Chevrolet materials and the 2018 Silverado manual explicitly describe AFM operation as V8-to-V4: four cylinders are deactivated and later reactivated. Current Chevrolet and GMC SUV engine listings use the name Dynamic Fuel Management (DFM). Those listings establish that specified engines have DFM, but the cited material does not provide its full control logic or specify that it follows the same fixed four-cylinder pattern described for AFM.
For that reason, “switches to four cylinders” is an accurate shorthand for the cited AFM explanation, not a confirmed description of every current GM V8 SUV. When checking a vehicle, use its exact model year and engine designation, and consult the manual or manufacturer information for that vehicle rather than assuming that all GM V8s have the same system or behavior.
Which GM V8 SUVs are listed with DFM?
The manufacturer specifications available here identify DFM on particular gasoline V8s in Chevrolet Tahoe and Suburban models and GMC Yukon models. The 2025 Tahoe/Suburban figures come from preliminary Chevrolet specifications released in November 2023; GMC’s Yukon engine guide lists the same output figures for its two V8s. The 2026 Suburban page provides current model-year trim availability and fuel recommendations. Horsepower and torque are manufacturer ratings, not fuel-economy measurements.
Rank #3
- ✅【Designed for Magsafe】 - The most fashionable iphone car mount in 2026 Magsafe is designed for iPhone 18 Pro Max/17/16/15/14/13/12 Pro Max Mini and official Magsafe cases and other magnetic phone cases and can be fixed directly to these phones without the need to affix metal plates. All Android Phones Will Work: Metal rings are provided; they fit cases and other phones without magsafe. Based on Unique Grandmaster Design (Protected by US Design Patent No. US D1,112,194 S)
- ✅【STRONG MAGNETIC MagSafe Car Mount】 - This powerful magnetic phone holder can create a powerful attraction that firmly supports your device while allowing you to drive without distraction. it easily and securely holds your phone through bumps, sharp turns or even sudden stops, no worrying of dropping your phone.
- ✅【SUPER STICK FORCE】 - VHB Dash Mounted Holders adhesive provides strong stick force between the dashboard and the car phone holder, which can firmly stick to any plane in the car, fix your device, adapt to a variety of road conditions such as sudden braking, speed bump, and rugged mountain road.
- ✅【SAFE DRIVING VIEW】 - Mini-size, not taking up space, it is placed in the dashboard without blocking the view at all, and does not need to look down at the device to ensure your safe driving. Cell Phone Car Mount is suitable for most cars, pickups, SUV, taxi; It is the best assistant for Uber and Lyft drivers
- ✅【360° FREE ROTATION】 - With an adjustable swivel ball joint, you can rotate your smartphone or device at your own will, providing the best viewing angle. Quickly pick and place with one hand, free your hands and make calls and GPS navigation more convenient
| Vehicle and model-year context | Engine listed with DFM | Manufacturer-rated output | Fuel recommendation or availability |
|---|---|---|---|
| 2025 Chevrolet Tahoe and Suburban; preliminary specifications announced November 29, 2023 | 5.3L gasoline V8 | 355 hp; 383 lb-ft | Fuel grade and trim details are not stated in the cited preliminary specification. |
| 2025 Chevrolet Tahoe and Suburban; preliminary specifications announced November 29, 2023 | 6.2L gasoline V8 | 420 hp; 460 lb-ft | Fuel grade and trim details are not stated in the cited preliminary specification. |
| GMC Yukon; current engine guide, publication date not stated | 5.3L gasoline V8 | 355 hp; 383 lb-ft | The guide also lists a 3.0L diesel option; the fuel grade for this V8 is not stated in the cited guide. |
| GMC Yukon; current engine guide, publication date not stated | 6.2L gasoline V8 | 420 hp; 460 lb-ft | The fuel grade for this V8 is not stated in the cited guide. |
| 2026 Chevrolet Suburban | 5.3L gasoline V8 | Output is not stated on the cited 2026 model-page material summarized here. | Standard except on High Country; regular 87-octane gasoline recommended. |
| 2026 Chevrolet Suburban | 6.2L gasoline V8 | Output is not stated on the cited 2026 model-page material summarized here. | Standard on High Country; available on RST, Z71 and Premier; premium 91-octane gasoline recommended. |
Trim availability and fuel specifications can change by model year and market, so verify the details for the exact vehicle being considered. The fuel-grade recommendations are separate from cylinder deactivation: they identify the recommended gasoline for the listed Suburban engine, not a cause of DFM operation or a measure of its fuel savings.
Free tools Windows power users keep installed
One-click scans. No signup required.
Does cylinder deactivation actually save fuel?
It can, when the engine has more capacity than the vehicle needs in that moment. Reducing engine work during a light-load situation can lower fuel use relative to operating all cylinders in the same conditions. Steady cruising is the example given in the AFM owner-manual description. Higher demand—including acceleration, climbing or hauling—can bring the engine back to full-cylinder operation, so the opportunity to use fewer cylinders varies over a drive.
Chevrolet/General Motors said in a 2011 AFM fact sheet that cylinder deactivation could improve fuel efficiency by “up to 12 percent.” Treat that wording as an older corporate maximum claim, not a typical result, a current-model test figure or a promise for a particular SUV, route or owner. The manufacturer materials cited here do not establish a current, SUV-specific real-world saving for AFM or DFM.
Rank #4
- Buyer's Guide: The seat guard for car seat between seat & console measures 15.75*2.7*1.53", suitable for gaps of 1.43-1.53" in width, please double-check carefully the distance between your seat and the center console before placing an order
- Storage and Filling in One: Differ from traditional single-function gap fillers, gap filler for car incorporates storage function, offers you the convenience of storing phones and various other items, so that you can access them at any time while driving
- Avoid Items Slipping: With the bumps and vibrations of the car, phones, keys may fall into the seat crevices, which is difficult to pick up, and distracts the driver's attention. Car gap seat filler fills gaps seamlessly to create an effective barrier
- Easy to Install: Car side seat gap filler is easy to install, simply insert it into the gap between the seat and the center console, gap seat filler for car can fit tightly without affecting the normal adjustment of the seat and the use of the seat belt
- Premium Material: Crafted from premium EVA material, our car seat side gap filler boasts a combination of wear-resistant, softness&durability. Maintenance is effortless, simply rinse and wipe to quickly clean the dust and debris in corners and crevices
Actual fuel economy also depends on the trip and how the vehicle is used. Route, speed, grade, load, traffic and driving behavior are relevant general considerations, but the cited material does not quantify how much each factor changes AFM or DFM savings. A vehicle that spends more time under light demand may have more occasions when deactivation can help than one frequently accelerating, climbing or carrying a heavy load; these examples explain the principle, not a measured comparison between vehicles or drivers.
Do not use the 12 percent figure to calculate an expected fuel bill, compare two SUV trims or infer that a specific engine will outperform another. A valid model-to-model savings comparison would need figures based on comparable model years, vehicle configurations, test cycles and measurement methods. Those comparative AFM/DFM figures are not established in the manufacturer material cited here.
How to check the system on a specific SUV
- Identify the model year and exact vehicle. A Tahoe, Suburban or Yukon name alone is not enough: engine and trim availability can differ between years.
- Confirm the engine. Check the window sticker, vehicle documentation or manufacturer specifications for the engine displacement and designation. Do not assume that every GM V8 SUV has cylinder deactivation.
- Check the system name in year-specific information. The cited current listings identify DFM on specified 5.3L and 6.2L V8s. Older AFM descriptions explain V4 operation, but they do not prove that DFM uses the identical strategy.
- Use the correct fuel recommendation. For the 2026 Suburban, Chevrolet recommends regular 87-octane gasoline for the 5.3L and premium 91-octane gasoline for the 6.2L. Follow the recommendation for the precise model year and engine; fuel grade is not an indicator of whether cylinder deactivation will engage.
- Keep performance ratings separate from economy claims. Horsepower and torque describe rated engine output. They do not say how often cylinders deactivate or how much fuel the system saves on a particular trip.
What these facts do—and do not—say about repairs
The AFM component names in Chevrolet’s fact sheet can help make repair terminology more intelligible: special valve lifters, a lifter oil manifold assembly and an engine control module are part of the system described there. They do not establish that these parts commonly fail, provide a failure rate, identify symptoms, set a replacement interval or show that a particular vehicle needs service.
Best Value
- 🔰 UPGRADED SIDE STORAGE DESIGN - Our console cover is thinner than the old one, universal for all seasons. There is an 8.66*5.12 inch storage pocket design on each left and right side, expanding the storage space, convenient and practical. Meet the storage needs of the main passenger seat, you can store your cell phone, keys, tissues, ID and some other small daily items.
- 🔰 PREMIUM MICROFIBER LEATHER MATERIAL - This car center console cover is made of quality microfiber leather material, soft and skin-friendly touch. Exquisite and fashionable diamond shaped stitching, every detail is in place. Inside the car center console cover is made of thickened memory foam, even after squeezing, it can slowly recover to its original shape.
- 🔰 RELIEVE DRIVING FATIGUE - The arm rest cover for car adopts ergonomic design, giving just the right amount of arm support, effectively dispersing elbow pressure and relieving driving fatigue. Protect your car's center console from getting dirty or scratched. Especially suitable for long time driving or long distance traveling, bringing you a new experience of relaxation and comfort!
- 🔰 NON-DESTRUCTIVE INSTALLATION - This car console cover is designed with an elastic band for a firm fit and not easy to shake. And the back side is full of protruding dots, which can effectively avoid the armrest cover from slipping and shifting. All you need to do is to open the center console cover, put the elastic band directly into the cover and then close it.
- 🔰 BUYER'S GUIDE - You will receive a car armrest storage box with the size of 12.13*7.80 inch, please measure the size of your car's armrest storage box before you buy. We have prepared five simple and beautiful colors for you, you can choose according to your own preferences. Suitable for most of the vehicles on the market, such as car, truck, SUV, RV, van, etc.
If a vehicle has a concern, an individual diagnosis requires vehicle-specific information and inspection. The material cited here does not support recommending a repair, an AFM/DFM delete, an aftermarket tune or a replacement part for a vehicle based only on its engine having cylinder deactivation. For a part purchase, confirm year, engine and fitment with vehicle-specific information; a category name such as “AFM lifter oil manifold assembly” does not validate a particular listing or establish a need to buy one.
Sources and scope
- Chevrolet/General Motors, 2011, “Turning V-8 Engines into V-4s – Chevrolet Offers Cylinder Deactivation to Save Fuel,” for AFM’s mechanism, component names, operating examples and the “up to 12 percent” claim.
- Chevrolet, 2018 Silverado Owner’s Manual, Active Fuel Management section, for the V4 cruising example and full-cylinder examples of acceleration, passing and merging.
- Chevrolet/General Motors Newsroom, November 29, 2023, “Meet the new 2025 Chevrolet Tahoe and Suburban,” for preliminary 2025 engine listings and output ratings.
- GMC, “GMC Yukon Engines: Choose Your Perfect Match,” for Yukon DFM engine listings and the 3.0L diesel option. The page’s publication date is not stated in the cited material.
- Chevrolet, “2026 Chevy Suburban | Large SUV,” for 2026 Suburban engine/trim availability and fuel recommendations.
The system and vehicle details above are limited to those official materials and the model years they describe. They do not establish DFM’s full control strategy, an independent fuel-economy result, or service guidance for a specific vehicle.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
