Lethal Garage Flex Fuel Kit - 2014-2019 GMC Sierra

  • Sale
  • $255.00
  • Regular price $329.95

This is a custom made E85 Flex Fuel kit for the 15-19 GMC Sierra with a 5.3L or 6.2L engine, assembled by Lethal Garage that includes the following.

  • 1 - GM OEM Flex Fuel Sensor
  • 1 - GM OEM Fuel Line 
  • 1 - Gen5DIY custom plug & play power harness
  • Two Year Warranty

Our product is designed to tuck away and be hidden under the vehicle away from the engine allowing 100% concealment if your hood is popped. Our kit installs under the back side of the cab in front of the fuel tank where the factory sensor would have installed if your vehicle came with it. 

Current Bonus Items:

  • $4.75 Priority Mail Shipping

Vehicle Fitment:

  • 2014 GMC Sierra 1500 models with the 5.3L or 6.2L engine
  • 2015-2018 GMC Sierra's with the 5.3L or 6.2L engine
  • 2019 GMC Sierra Limited Edition model with the 5.3L or 6.2L engine
  • 2019 GMC Sierra HD models with the 5.3L or 6.2L engine


  • This kits harness uses OEM connectors in tandem with OEM products. Fit and finish look 100% stock under your vehicle. Your car will pick up 15-35rwhp on e78 or better depending on the tune.
  • Note: While the GM flex fuel sensor can be installed and works perfectly fine to run pump gas with your vehicle without a tune, to run E85 your truck must have a tune to run E85 fuel. 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.

Install Guide: 

Note: Verify your truck or SUV has the Flex Fuel harness plug located on the frame rail of the vehicle just behind the cab of the truck. See the install video for precise location. 



WARNING California Residents - cancer (and/or reproductive harm) - www.P65Warnings.ca.gov.