20 Best Air Fuel Ratio Gauge [2022]

Are you looking for the best air fuel ratio gauge? Based on expert reviews, we ranked them. We've listed our top-ranked picks, including the top-selling air fuel ratio gauge.

We Recommended:

# Preview Product
1 AEM (30-4110) UEGO Air/Fuel Ratio Gauge AEM (30-4110) UEGO Air/Fuel Ratio Gauge
2 GlowShift Black 7 Color Dual Digital Wideband Air / Fuel Ratio AFR Gauge Kit - Includes Oxygen... GlowShift Black 7 Color Dual Digital Wideband Air / Fuel Ratio AFR Gauge Kit - Includes Oxygen...
3 Innovate Motorsports (3882 SCG-1 Solenoid Boost Controller and Air/Fuel Ratio Gauge Kit, White,... Innovate Motorsports (3882 SCG-1 Solenoid Boost Controller and Air/Fuel Ratio Gauge Kit, White,...
4 AEM 52mm X-Series Gauge Kit Wideband Air/Fuel & Oil/Fuel Pressure & Boost Turbo w/MAP Lanyard Black AEM 52mm X-Series Gauge Kit Wideband Air/Fuel & Oil/Fuel Pressure & Boost Turbo w/MAP Lanyard Black
5 Auto Meter 4379 Ultra-Lite Wide Band Air Fuel Ratio Kit,2.3125 in. Auto Meter 4379 Ultra-Lite Wide Band Air Fuel Ratio Kit,2.3125 in.
6 GlowShift Black 7 Color Digital Wideband Air / Fuel Ratio AFR Gauge Kit - Includes Oxygen Sensor,... GlowShift Black 7 Color Digital Wideband Air / Fuel Ratio AFR Gauge Kit - Includes Oxygen Sensor,...
7 30-4110 UEGO Air/Fuel Ratio Gauge AFR 52mm with 4.9 LSU Sensor, wideband Sensor, WideBand A/F Ratio... 30-4110 UEGO Air/Fuel Ratio Gauge AFR 52mm with 4.9 LSU Sensor, wideband Sensor, WideBand A/F...
8 AEM 30-0300 X-Series Wideband UEGO AFR Sensor Controller Gauge AEM 30-0300 X-Series Wideband UEGO AFR Sensor Controller Gauge
9 Wideband UEGO Air/Fuel Ratio Gauge 52mm (2-1/16”) with 4.9 LSU Sensor, Digital AFR Controller... Wideband UEGO Air/Fuel Ratio Gauge 52mm (2-1/16”) with 4.9 LSU Sensor, Digital AFR Controller...
10 GlowShift Tinted 7 Color Narrowband Air/Fuel Ratio AFR Gauge - Lean, Optimal & Rich Readings - Black... GlowShift Tinted 7 Color Narrowband Air/Fuel Ratio AFR Gauge - Lean, Optimal & Rich Readings -...
11 AEM 52mm Wideband UEGO Air Fuel Ratio Sensor Controller Gauge w/White Face Kit AEM 52mm Wideband UEGO Air Fuel Ratio Sensor Controller Gauge w/White Face Kit
12 AEM 52mm Gauge Combo Air/Fuel Ratio Wideband UEGO & Oil Pressure 150psi & Boost 30-35 w/MAP Lanyard... AEM 52mm Gauge Combo Air/Fuel Ratio Wideband UEGO & Oil Pressure 150psi & Boost 30-35 w/MAP...
13 AEM 2 Gauge Display Set UEGO WideBand Air/Fuel Ratio Gauge + Boost Pressure Gauge -30-35psi +... AEM 2 Gauge Display Set UEGO WideBand Air/Fuel Ratio Gauge + Boost Pressure Gauge -30-35psi +...
14 Innovate Motorsports (3837) LM-2 (BASIC) Digital Air/Fuel Ratio Wideband Meter incl. Bosch LSU 4.9 ,... Innovate Motorsports (3837) LM-2 (BASIC) Digital Air/Fuel Ratio Wideband Meter incl. Bosch LSU 4.9...
15 30-4110 UEGO Air/Fuel Ratio Gauge,37301001 Gauge-Type UEGO Controller,O2 Control Sensor Kit 30-4110 UEGO Air/Fuel Ratio Gauge,37301001 Gauge-Type UEGO Controller,O2 Control Sensor Kit
16 ARTILAURA 2-1/16' 52mm Air/Fuel Ratio Gauge LED Digital Display with Narrowband O2 Oxygen Sensor Car... ARTILAURA 2-1/16" 52mm Air/Fuel Ratio Gauge LED Digital Display with Narrowband O2 Oxygen Sensor...
17 Innovate Motorsports 3903 Ecf-1 Advanced 4 in 1Complete Gauge Kit, 1 Pack Innovate Motorsports 3903 Ecf-1 Advanced 4 in 1Complete Gauge Kit, 1 Pack
18 AEM 52mm X-Series Gauge Kit Wideband Air/Fuel UEGO & Boost Pressure 35PSI 2.5Bar w/MAP Lanyard Black AEM 52mm X-Series Gauge Kit Wideband Air/Fuel UEGO & Boost Pressure 35PSI 2.5Bar w/MAP Lanyard Black
19 Innovate Motorsports 3894 LM-2 Dual Air/Fuel Ratio Meter (2 Oxygen Basic Kit) Innovate Motorsports 3894 LM-2 Dual Air/Fuel Ratio Meter (2 Oxygen Basic Kit)
20 HOTSYSTEM Universal Electronic Air/Fuel Ratio Monitor Meter Gauge Blue Digital LED 2inches 52mm for... HOTSYSTEM Universal Electronic Air/Fuel Ratio Monitor Meter Gauge Blue Digital LED 2inches 52mm...
SaleBestseller No. 1
AEM (30-4110) UEGO Air/Fuel Ratio Gauge
  • Interchangeable black and white faceplates included for customizing gauge appearance
  • Bosch 4.9 LSU wideband sensor and weld-in bung included PN 30-4110
  • No free air sensor calibration required ever. A 2-1/16 inch gauge housing ensures that it will fit in most gauge pods and can be remotely mounted...
  • Interchangeable black and silver bezels included. 52mm (2-1/16”) gauge housing
  • 0-5V analog output 10-20 AFR range only
Bestseller No. 2
GlowShift Black 7 Color Dual Digital Wideband Air / Fuel Ratio AFR Gauge Kit - Includes Oxygen...
  • GlowShift Black 7 Color Series Dual Wideband Air/Fuel Ratio Gauge is Essential for Tuning & Mapping Out the Air to Fuel Ratios of the Left & Right...
  • Gasoline Wideband Air/Fuel Ratio Readings from 10.00 to 20.00 AFR - E85 Wideband Air/Fuel Ratio Readings from 6.00 to 12.00 AFR- 2-1/16" (52mm) Gauge...
  • 7 Solid Color Modes & 2 Color Cycle Modes Allow You to Match Your Factory Dashboard Lights or Add a Custom Style to the Interior of Your Vehicle -...
  • Includes (2) 4.9 LSU Wideband Oxygen Sensors, (2) Stainless Steel Weld-In Bungs, (2) Mild Steel Weld-In Bungs, (2) Control Boxes, (2) 10' Sensor...
  • GlowShift Guarantee with One Year Limited Warranty & Free Lifetime Technical Support
SaleBestseller No. 3
Innovate Motorsports (3882 SCG-1 Solenoid Boost Controller and Air/Fuel Ratio Gauge Kit, White,...
  • User programmable boost cut safety using Air/Fuel and Pressure references
  • Programmable waste gate reference pressure threshold
  • Programmable solenoid duty cycle with separate gain control function
  • Programmable shift light & OLED user configurable display
  • No PC required for configuration and use (Required for data logging)
Bestseller No. 4
AEM 52mm X-Series Gauge Kit Wideband Air/Fuel & Oil/Fuel Pressure & Boost Turbo w/MAP Lanyard Black
  • This AEM 3 gauge kit is a popular combo Compatible with commonly used gauges and Compatible with. Our official MAPerformance lanyard included as a...
  • AEMs 30-0306 X-Series -30in/Hg~35PSI / -1~2.5BAR Digital Boost Display gauge combines incredible looks, increased readability and a multitude of new,...
  • AEMs 30-0301 X-Series 100 PSI/7 BAR Digital Oil/Fuel Pressure gauge combines incredible looks, increased readability and a multitude of new,...
  • The X-Series Wideband UEGO AFR Sensor Controller Gauge (PN 30-0300) measures 2 1/16th-inch (52mm) in diameter, and features a modern, visually...
  • Slim 0.825 overall gauge depth and 0.200 cup depth mount them virtually anywhere! Black faceplates and bezels included.
Bestseller No. 5
Auto Meter 4379 Ultra-Lite Wide Band Air Fuel Ratio Kit,2.3125 in.
  • Gauge kit includes custom tuned .1 AFR Resolution Bosch LSU4.2 Sensor, 8ft. wiring harness, 304 stainless steel weld-in bung, mounting hardware, and...
  • 0-4v data output feed for ECU, data acquisition unit, or Laptop tuning
  • Suitable for use with gasoline powered engines
  • Digital segment display and LED radial bar graph display
  • 12 and 16 volt compatible, compatible with nearly every street car or race car electrical system
Bestseller No. 6
GlowShift Black 7 Color Digital Wideband Air / Fuel Ratio AFR Gauge Kit - Includes Oxygen Sensor,...
  • GlowShift Black 7 Color Series Digital Wideband Air/Fuel Ratio Gauge is Essential for Tuning & Mapping Out the Air to Fuel Ratios of Your Gasoline or...
  • Gasoline Wideband Air/Fuel Ratio Readings from 10.00 to 20.00 AFR - E85 Wideband Air/Fuel Ratio Readings from 6.00 to 12.00 AFR- 2-1/16" (52mm) Gauge...
  • 7 Solid Color Modes & 2 Color Cycle Modes Allow You to Match Your Factory Dashboard Lights or Add a Custom Style to the Interior of Your Vehicle -...
  • Includes 4.9 LSU Wideband Oxygen Sensor, Weld-In Bung, Control Box, 10' Sensor Harness, 7' Gauge to Control Box Harness, 5' Power Harness, 3' Data...
  • GlowShift Guarantee with One Year Limited Warranty & Free Lifetime Technical Support
Bestseller No. 7
30-4110 UEGO Air/Fuel Ratio Gauge AFR 52mm with 4.9 LSU Sensor, wideband Sensor, WideBand A/F Ratio...
  • 🔧[WARRANTY] - Please don't worry about the quality of the product, our 30-4110 provide a lifetime warranty, if you have any quality problems after...
  • 🔧[AIR/FUEL RATIO GAUGE] - UEGO Air/Fuel Ratio Gauge is a broadband UEGO Air/Fuel Ratio Controller (AFR) and instrumentation in one. It combines...
  • 🔧[FUNCTION] - Accurate AFR data is critical when tuning an engine. Using a wideband air/fuel controller during the tuning process allows you to...
  • 🔧[HIGH QUALITY] - Every air fuel ratio gauge features a 0-5V analog output, compatible with data loggers and practically any engine management...
  • 🔧[INSTALL] - Thanks to its 52mm housing, the versatile gauge will fit into the majority of gauge pods. The gauge also features interchangeable...
Bestseller No. 8
AEM 30-0300 X-Series Wideband UEGO AFR Sensor Controller Gauge
  • The X-Series wideband UEGO AFR sensor controller gauge (PN 30-0300) features a modern, visually striking faceplate and new seven-segment, center...
  • The gauge includes a 0-5v and RS232 Serial Port output for feedback control and data logging, and an AEMnet (CANbus) output for data logging
  • X-Digital wideband technology gives these controllers the ability to read and report values that other controllers do not, which can deliver more...
  • Faster response time improves wideband feedback control, and can provide a safer, more powerful and accurate tune
  • When tuning an engine using wideband AFR feedback control on an inertia dyno, dead time affects the data you are looking at because it is reported in...
Bestseller No. 9
Wideband UEGO Air/Fuel Ratio Gauge 52mm (2-1/16”) with 4.9 LSU Sensor, Digital AFR Controller...
  • 【AIR/FUEL RATIO UEGO GAUGE】Our wideband O2 AFR gauge has a digital LED display and LED "needle" that changes color as the AFR changes...

  • 【WIDELY COMPATIBILITY】The 52 mm (2-1/16 inch) gauge housing ensures that it fits most instrument pods and can be installed remotely...

  • 【PREMIUM QUALITY】Accurate A/F ratio data is crucial when adjusting the engine. The 4.9 LSU sensor provides speed and accuracy for the...

  • 【INSTALLATION】Thanks to the 52mm housing of the wideband gauge, you can install it almost wherever feasible. Plug and play, very...

  • 【100% SATISFACTION SERVICE】If you have any questions or dissatisfaction, please email us and we will help you solve it perfectly - 24...

SaleBestseller No. 10
GlowShift Tinted 7 Color Narrowband Air/Fuel Ratio AFR Gauge - Lean, Optimal & Rich Readings - Black...
  • GlowShift Tinted 7 Color Series Narrowband Air/Fuel Ratio Gauge Monitors & Displays Your Engine's Air to Fuel Mixture by Reading the Voltage Output of...
  • Narrowband Air/Fuel Ratio Readings from Lean, Optimal & Rich Mixtures - 2-1/16" (52mm) Gauge with Black Dial, Tinted Lens & Illuminated Red Needle
  • 7 Solid Color Modes & 2 Color Cycle Modes Allow You to Match Your Factory Dashboard Lights or Add a Custom Style to the Interior of Your Vehicle -...
  • Includes 2' Power Harness with 6' Sensor Lead Wire, Gauge Visor, Mounting Hardware & Installation Instructions
  • GlowShift Guarantee with One Year Limited Warranty & Free Lifetime Technical Support
Bestseller No. 11
AEM 52mm Wideband UEGO Air Fuel Ratio Sensor Controller Gauge w/White Face Kit
  • X-Series Wideband UEGO AFR Controller Gauge were fastest responding wideband air/fuel ratio controllers in an independent test vs. 17 competitor...
  • Black bezel and black dual faced faceplate, silver bezel/white gauge option included.
  • Display Lambda values from .55 to 2.00
  • Factory calibrated resistor does not require free-air calibration, but technology allows for free-air calibration as sensor ages if user desires.
  • Includes Bosch 4.9LSU wideband UEGO sensor. 52mm gauge diameter and slim 0.825� gauge depth.
Bestseller No. 12
AEM 52mm Gauge Combo Air/Fuel Ratio Wideband UEGO & Oil Pressure 150psi & Boost 30-35 w/MAP Lanyard...
  • Our AEM three gauge kit is a popular combo Compatible with commonly used gauges and application. Our official MAPerformance lanyard included as a...
  • AEMs legendary Digital Wideband O2 AFR UEGO Gauge is a wideband UEGO air/fuel ratio controller (AFR) and gauge in one.
  • AEM's Digital Boost Display Gauges combine unsurpassed accuracy, speed and control with an easy-to-read digital LED interface that displays boost in 1...
  • AEM Digital Oil Pressure Gauges combine unsurpassed accuracy, speed and control with an easy-to-read digital LED interface that displays oil pressure...
  • Standard 52mm (2-1/16) gauge housing
Bestseller No. 13
AEM 2 Gauge Display Set UEGO WideBand Air/Fuel Ratio Gauge + Boost Pressure Gauge -30-35psi +...
  • 2 popular AEM gauges in a convenient combo set.
  • All gauges are brand new, complete in box.
  • Set Includes: AEM Wideband UEGO Air/Fuel Ratio Gauge 30-4110, AEM Boost Display Gauge (-30-35PSI) 30-4406, MAP Lanyard.
  • This gauge is easy to read, highly accurate, and controls its data by a digital LED display and LED needle that will change colors as the ratios...
  • Complete stand alone gauges.
Bestseller No. 14
Innovate Motorsports (3837) LM-2 (BASIC) Digital Air/Fuel Ratio Wideband Meter incl. Bosch LSU 4.9 ,...
  • Patented “Direct Digital” Wideband Technology
  • Wideband O2 sensor (Bosch LSU 4.9) is compatible with most fuel types (leaded, unleaded, diesel, methanol, E85, etc)
  • includes the LM-2, Bosch LSU 4.9, 8 ft sensor cable, cigarette-lighter power, USB cable, weld-in bung and plug, and quick-start guide.
  • Positive lock connectors for all connections
Bestseller No. 15
30-4110 UEGO Air/Fuel Ratio Gauge,37301001 Gauge-Type UEGO Controller,O2 Control Sensor Kit
  • 【Product Details】30-4110 UEGO Air/Fuel Ratio Gauge,0-5V analog output 10-20 AFR range only.Our UEGO air-fuel ratio meter is a broadband UEGO...
  • 【Product advantages】The latest X-Digital broadband technology enables these controllers to read and report values that cannot be read by other...
  • 【Installation Notes】Product design is user-friendly, easy to install. No free air sensor calibration required ever and you can use it directly....
  • 【Quality assurance】Original product.All item was tested well working before sent out, Any quality problems within 1 month can be replaced free of...
  • 【SERVICE GUARANTEE】 Committed to providing consumers with the best cost-effective products, If you have any questions during the use, please...
Bestseller No. 16
ARTILAURA 2-1/16" 52mm Air/Fuel Ratio Gauge LED Digital Display with Narrowband O2 Oxygen Sensor Car...
  • 🚗【Function】Numbers clearly show, LED backlit for easy reading in the darkness.
  • 🚗【Range】 2-1/16" (52mm) gauge with black dial. Air/Fuel Ratio readings from 10.00 to 20.00 AFR.
  • 🚗【Applicability】Air Fuel Ratio gauge compatible for 12 volt car. High sensitivity and easy operation.
  • ✅【Oxygen Sensor】Oxygen Sensor OEM:0258006028, Working Voltage: DC12V, Spiral: M18*1.5, Use Wrench: 22mm, Output Voltage: Maximum value ≥900mv/...
  • ⭐⭐⭐⭐⭐[After-Sale Guarantee]Includes 1x Air Fuel AFR Gauge, 1x Narrowband Oxygen Sensor, 1x English Manual. Please contact us if you are...
SaleBestseller No. 17
Innovate Motorsports 3903 Ecf-1 Advanced 4 in 1Complete Gauge Kit, 1 Pack
  • Four-in-one, ethanol content percentage, fuel temperature, fuel pressure, and wideband air/fuel ratio gauge
  • OLED user configurable display (one, two, or four channel viewing modes)
  • 0-145 psi (10 bar) fuel pressure sensor
  • 2 1/6 inch diameter gauge body with interchangeable faceplates and bezels
Bestseller No. 18
AEM 52mm X-Series Gauge Kit Wideband Air/Fuel UEGO & Boost Pressure 35PSI 2.5Bar w/MAP Lanyard Black
  • This AEM 2 gauge kit is a popular combo for commonly used gauges and applications. Our official MAPerformance lanyard included as a special bonus!
  • AEMs 30-0306 X-Series -30in/Hg~35PSI / -1~2.5BAR Digital Boost Display gauge combines incredible looks, increased readability and a multitude of new,...
  • The X-Series Wideband UEGO AFR Sensor Controller Gauge (PN 30-0300) measures 2 1/16th-inch (52mm) in diameter, and features a modern, visually...
  • X-Series Wideband UEGO AFR Controller Gauge were fastest responding wideband air/fuel ratio controllers in an independent test vs. 17 competitor...
  • Slim 0.825 overall gauge depth and 0.200 cup depth mount them virtually anywhere! Black faceplates and bezels included.
SaleBestseller No. 19
Innovate Motorsports 3894 LM-2 Dual Air/Fuel Ratio Meter (2 Oxygen Basic Kit)
  • Wideband O2 Compatible with several fuel types -Leaded, Unleaded, Diesel, E85 & more
  • Monitor left and right exhaust banks on one single meter. Perfect for V8's
  • User configurable display, AFR or Lambda. OBD-II Scan tool- read/clear DTCs and log up to 16 channels of CAN OBD-II Data
  • Datalog up to 32 channels with optional accessories. Built-in RPM converter-direct frequency or with optional inductive clamp
  • 4 fully-differential analog inputs, 2 configurable linear analog outputs
Bestseller No. 20
HOTSYSTEM Universal Electronic Air/Fuel Ratio Monitor Meter Gauge Blue Digital LED 2inches 52mm for...
  • Accuracy of analog LED type:Every 0.5%,using BAR type to light up.
  • Display range:Digital type is from 20.0% to 10.0%;Analog LED type is from 20.0% to 10.0%;Both of digital type and analog LED type will show the...
  • Warning(Red Light):At start, the voltage is lower than 11.0V,the value of AIR/FUEL is lower than 0.8 or higher than 10BAR(lower than 12 or higher than...
  • Direct analog:The digital has 20 LED pcs, 10.0%≤Air/Fuel ratio≤12.5%,the LED lights appear green among 6pcs; 13.0%≤ratio≤17.5%, the LED lights...
  • Easy installation:Our gauge includes electric wire with necessary mounting and installation hardware,no need other sensor, your existing oxygen sensor...

Having trouble finding a great air fuel ratio gauge?

This problem is well understood by us because we have gone through the entire air fuel ratio gauge research process ourselves, which is why we have put together a comprehensive list of the best air fuel ratio gauges available in the market today.

After hours of searching and using all the models on the market, we have found the best air fuel ratio gauge for 2022. See our ranking below!

How Do You Buy The Best Air Fuel Ratio Gauge?

Do you get stressed out thinking about shopping for a great air fuel ratio gauge? Do doubts keep creeping into your mind?

We understand, because we’ve already gone through the whole process of researching air fuel ratio gauge, which is why we have assembled a comprehensive list of the greatest air fuel ratio gauge available in the current market. We’ve also come up with a list of questions that you probably have yourself.

John Harvards has done the best we can with our thoughts and recommendations, but it’s still crucial that you do thorough research on your own for air fuel ratio gauge that you consider buying. Your questions might include the following:

  • Is it worth buying an air fuel ratio gauge?
  • What benefits are there with buying an air fuel ratio gauge?
  • What factors deserve consideration when shopping for an effective air fuel ratio gauge?
  • Why is it crucial to invest in any air fuel ratio gauge, much less the best one?
  • Which air fuel ratio gauge are good in the current market?
  • Where can you find information like this about air fuel ratio gauge?

We’re convinced that you likely have far more questions than just these regarding air fuel ratio gauge, and the only real way to satisfy your need for knowledge is to get information from as many reputable online sources as you possibly can.

Potential sources can include buying guides for air fuel ratio gauge, rating websites, word-of-mouth testimonials, online forums, and product reviews. Thorough and mindful research is crucial to making sure you get your hands on the best-possible air fuel ratio gauge. Make sure that you are only using trustworthy and credible websites and sources.

John Harvards provides an air fuel ratio gauge buying guide, and the information is totally objective and authentic. We employ both AI and big data in proofreading the collected information.

How did we create this buying guide? We did it using a custom-created selection of algorithms that lets us manifest a top-10 list of the best available air fuel ratio gauge currently available on the market.

This technology we use to assemble our list depends on a variety of factors, including but not limited to the following:

  1. Brand Value: Every brand of air fuel ratio gauge has a value all its own. Most brands offer some sort of unique selling proposition that’s supposed to bring something different to the table than their competitors.
  2. Features: What bells and whistles matter for an air fuel ratio gauge?
  3. Specifications: How powerful they are can be measured.
  4. Product Value: This simply is how much bang for the buck you get from your air fuel ratio gauge.
  5. Customer Ratings: Number ratings grade air fuel ratio gauge objectively.
  6. Customer Reviews: Closely related to ratings, these paragraphs give you first-hand and detailed information from real-world users about their air fuel ratio gauge.
  7. Product Quality: You don’t always get what you pay for with an air fuel ratio gauge, sometimes less, and sometimes more.
  8. Product Reliability: How sturdy and durable an air fuel ratio gauge is should be an indication of how long it will work out for you.

John Harvards always remembers that maintaining air fuel ratio gauge information to stay current is a top priority, which is why we are constantly updating our websites. Learn more about us using online sources.

If you think that anything we present here regarding air fuel ratio gauge is irrelevant, incorrect, misleading, or erroneous, then please let us know promptly!

Related Post:

FAQ:

Q: What does the fuel gauge tell you?

A: The fuel gauge only shows an approximation of how much gas is in the tank. Driving on an uneven surface will cause the needle to vary from true. For example, while driving up or down an incline the needle may indicate a full tank of gas, while on a flat road it indicates only a half full tank.

Q: What is the fuel pressure gauge?

A: Fuel Pressure Gauge. Fuel pressure gauges are instruments that are used to measure and indicate the amount of fuel in a fuel tank. Fuel is one of the essential ingredients in combustion, and fuel pressure gages help to ensure that sufficient quantities of fuel are available in order to make combustion possible.

Q: What is an air fuel gauge?

A: An air–fuel ratio meter monitors the air–fuel ratio of an internal combustion engine. Also called air–fuel ratio gauge, air–fuel meter, or air–fuel gauge. It reads the voltage output of an oxygen sensor, sometimes also called AFR sensor or lambda sensor , whether it be from a narrow band or wide band oxygen sensor.