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Our Flex Fuel kits are in stock and ready to ship!

2008-2010 Hummer H3 Lethal Garage Flex Fuel Kit

Regular price $289.99 Sale price $329.99

Unit price per 

Our custom E85 Flex Fuel kit for the 08-10 Hummer H3 w/ LH8 5.3L V8 is just what you need for more power, savings on fuel costs, and a better-smelling ride... (Okay, that last one is subjective). This kit includes the following:

  • 1 - GM OEM Flex Fuel Sensor
  • 1 - Stainless Steel Braided PTFE OEM Style Fuel Line (Made in the USA)
  • 1 - Gen5DIY custom plug & play power harness & ECU tap. (Made in the USA)
  • Fuel Disconnect Tool (Design and brand may vary)
  • Two Two-year warranty on all GM parts as provided by GM & lifetime warranty on the Gen5DIY harness that covers any defects in craftsmanship.  

Our product is designed to tuck away and be hidden alongside your vehicle's power harness and lines. The harness is wrapped the same as the factory wires to allow it to blend in and not stand out. 


  • The H3 Hummer w/ LH8 5.3L V8 can run E85 with just this kit and a tune. But your stock fueling system will be maxed out. Consider fuel system upgrades if you plan to build your engine any further.
  • This kits harness uses OEM connectors in tandem with OEM products. Fit and finish look 100% stock under the hood. Depending on the tune, an H3 will pick up 8-12rwhp on e78 or better.
  • Note: While our flex fuel sensor can be installed and works perfectly fine to run pump gas with your H3 without a tune, to run E85 your H3 must have a tune to run E85 fuel. DO NOT INSTALL & RUN E85 WITHOUT A PROPER TUNE. Ensure your tuner has verified that your sensor is hooked up and reading the ethanol content before adding e85 to your vehicle. 

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

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