Downstream sensors don't cause these codes. They are self-tested prior to execution of the cat efficiency test. Gasoline quality is also not an issue. Same for the MAF.

Your choices are:

PCM reflash
MIL Eliminators
New pre-cats
Black tape over the CEL
Ignoring the CEL completely

Steve

98 Contour SE Sport 2.5 Duratec ATX The wifey's car 89 Taurus SHO - 246K miles 94 SHO ATX - 190K 1997 F-150 5.4L ATX - The Workhorse 150K. ANY THREAD WITH "OMG" or "WTF" ETC IN THE TITLE WILL BE IGNORED!