I am planning on replacing my O2 sensors this weekend in hopes to clear some lights on my dash. I have been wanting to Seafoam my engine also, but don't really feel like doing it right now. Would it be stupid for me to change my O2 sensors before Seafoaming, or will it have no effect on the new sensors? I know I will need to change my plugs after Seafoaming, so I guess I am just curious what else I should change and what order I should do all the work...