so defiantly don't have an eliminator on the 1st 02 sensor? bc the only way i can get it off is if i take the entire header off.You still use BOTH O2 sensors. The primary goes in the header, the secondary screws into the eliminator which screws into the s pipe. You can use an antifouler like foques said. If one dies not work, you can "stack" 2 of them for 10 bucks.