Review on 🚀 Innovative Performance Chip/Power Programmer for GMC Sierra 1500 2.7L, 3.0L, 4.3L, 4.8L, 5.0L, 5.3L, 5.7L, 6.0L, 6.2L engines - Enhance Fuel Efficiency, Save Gas & Boost MPG, Amplify Horsepower & Torque! by Jason Spainhour

I returned 2 after finding out it was just tricking the PCM into thinking the engine was hotter than it actually was and my fan was running the whole time, even on a cold start the fan was running the whole time time at maximum speed . After shutting down and cleaning the PCM, the fan worked fine. Looks like they only refunded 1. Spend the money and buy a real programmer or go to a good performance store and record your engine's performance and then program the PCM to actually increase your engine's performance. Not worth the money lost. But we are worth the lesson learned!