Three days after getting a new manifold catalytic converter installed on my 2010 Mazda 3 S, the check engine light came on again with a new code: P2096, post catalyst fuel trim too lean. After checking the connections on the fuel injectors, I noticed that one of them was leaking. Occasionally the car would not start up right away when the engine was warm, even though I had replaced the spark plugs. I plan to replace all four fuel injectors, but I do not yet know if this will solve the problem.