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 Jeff Leu

I returned 2 after finding out it just tricked the PCM into believing the engine was running at a higher temperature than it actually did and my fan kept running even when it was a cold fan start, top speed worked all the time. After removing 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!