guys, you all are correct. above 6000 rpms the mavericks do not use the stock o2 sensors and are a base tune. so if you have done mods to your motor, you are starving for fuel. the dobeck gen 4 can be programmed to only work after/ at 6000 rpms to redline. this will read the a/f each time the injector fires and make changes. real world changes just like the factory system does under 6000 rpms. it works great. for the guys that dont care about the check engine light, you can run the gen 4 for the entire rpm band, idle to redline. another thing that you guys can do is get a gen 3 programmer that will only work for over 6000 rpms, and tune only the red zone, and it can be programmed to only come on then, rpm based, and not load based. lots of options over the power commanders.