p0131/p0031 toggle...HELP PLEASE!!

have an '05 Legacy Sedan with a 2.5I that throws p0131 and p0031 consistently. eats the a/f sensors...haven't had one last for more than 9 months or 15,000 miles for three years...CEL will come on for p0131...replace a/f sensor...CEL will come on for p0031...replace a/f sensor and so on and so on...if it comes in for one code you can bet money the next time the other code sets...have replaced numerous sensors and the a/c relay but cannot find the gremlin...anybody else ever come across this type of thing?

Hi tuckeroo, I'm sure a techy will be along soon to comment. While you are waiting, why dont you drop a note in the New Members section to introduce yourself and tell us what you do, apart from banging your head against a wall with this Legacy.

how old are your plugs/leads?

am sure they have coilpacks on these gav

vehicle has been dealership maintained(we are the dealership lol) so plugs are good and we don't generally replace wires unless there is a problem...starts fine, runs fine, no misfire codes...always p0131(i was wrong about the toggling...was thinking of another vehicle with similar problem)checked connections. harnesses, resistance,replaced a/c relay as advised, and all the diag always leads to a/f replacement...there had GOT to be something else we just don't know where else to run with it

or aye, its 05 ha, bad crack when the dealers cant fix yer car haha

lol...just got some new info and will keep updated