Codes P1188/1189 and PO300

[Professor C]

My 2000 323ci recently failed emissions, and codes P1188, P1189, PO304/5/6 came up. My local mechanic, who has only the general diagnostic software, says he doesn't see an oxygen sensor problem, and he replaced the fuel filter last year. I put some Lucas fuel injector cleaner in at the last fill-up, but don't see a difference. I'm reluctant to take the car to the dealership until I am armed with a little more info. Any advice, thoughts, suggestions? I have taken a basics auto class but am willing to tackle bigger projects. Thanks in advance.

Professor C.