how many oxegen sensers on a 2007 camry with a v6 on 2007 Toyota Camry

mechanic replaced oxgen senser a week ago. check engine light came back on . now they say another one needs to be replaced and if that don't work the manifold needs replacing

2 answers
My Camry did the same thing and so did my friends Camry but after both sensors changed no more lights.
There's 4 of them, and I would take it someplace who can test it and not speculate on 'maybe'. Try Kansas City mechanics, there is a lot of trouble with mechanics in Potwin.