6.1 Swap Won't Rev Past 3K HELLLLPPPPP!!!

yeah, there are 4 listed, 2 up and 2 down, they are about $24 a pop at rockauto. the entire EFI is based on the inputs of these O2's especially the upstream as they tell the ECU the duty cycle of the injectors to get the proper A/F ratio. downstreams are mainly used to determine the condition of the cats. without O2 sensors the ECU is always in cold loop mode and perhaps that 3K rev limited.