I believe one of the O2 sensors has failed on my Toyota Tacoma. It has one before the cat and one after. Which one is most likely to fail first? Is there a way of checking which one has failed? Thanks, Tyler _______________________________________________ Diy_efi mailing list Diy_efi at diy-efi.org http://www.diy-efi.org/mailman/listinfo/diy_efi