I have 1992 Land Cruiser that has codes 21 and 28 on . I have tried clearing them and they have came back . The car sat for two years before i bought it . So I bought the replacement sensors after finding one covered in rust underneath the driver side door in the exhaust . Where is the other sensor located ? I am having a real trouble finding it for some reason . Any help would be greatly appreciated ? Thanks in advanced and I look forward to being here