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Lethal Garage Flex Fuel Kits are In-Stock and Shipping! Snag your Spring Savings NOW!

2019-2022 GMC Sierra 1500 Lethal Garage Flex Fuel Kit

Regular price $329.99 Sale price $399.99

Unit price per 

only 0 left in stock

Our custom E85 Flex Fuel kit for the 19-22 GMC Sierra 1500 (New Body) with a 5.3L or 6.2L engine that does not have Global B (Will not work for 2023+ Trucks) ECU is just what you need for more power, fuel savings, and a better-smelling ride. (Okay, that last one is subjective.) A tune is required to run E85!

Lethal Garage assembles this kit, and it includes the following:

  • 1 - GM OEM Flex Fuel Sensor
  • 1 - Stainless Steel Braided PTFE OEM Style Fuel Line (Made in the USA)
  • 1 - Fuel Line Disconnect Tool (Made in the USA)
  • 1 - Custom plug & play power harness & ECU tap. (Made in the USA)
  • Two Two-year warranty on all GM parts & lifetime warranty on the Gen5DIY harness that covers any defects in craftsmanship.
  • Includes zip ties for a clean install.

This kit installs under the hood, pulls power from the EVAP, and directly pins into your ECU. The fit and finish allow this product to be tucked away and mounted where no one would know your vehicle is running E85.  

Note: Tuning these trucks is not cheap and requires unlocking and purchasing tokens vid HPTuners. Please talk with your local shop to understand the costs of tuning before purchasing this kit or any kit on the market. 

Vehicle Fitment:

  • 2019-2022 GMC Sierra 1500 with the 5.3L or 6.2L engine
  • This will not work for the 2023-2024+models.


  • This kit harness uses OEM connectors in tandem with OEM products. Fit and finish look 100% stock under your vehicle's hood. Depending on the tune, your truck will pick up 15-25rwhp on e78 or better.
  • While this kit can be installed and will work perfectly fine to run pump gas without a tune, to run E85 your truck must have a tune. DO NOT INSTALL & RUN E85 WITHOUT A PROPER TUNE. Make sure your tuner has verified your sensor is hooked up and reading the ethanol content before adding E85 to your vehicle.
  • Until your vehicle is tuned and the flex sensor is turned on in the ECU, you may have a CEL (Check Engine Light), as the ECU won't know what you plugged into it until it is tuned.

Install Guide: 


~Coming Soon~


WARNING California Residents - cancer (and/or reproductive harm) -

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