Help with Increased Emissions

[Braxx5]

So my CEL came on in my 04 530i, with an increased emissions showing on the dash. I went to Auto Zone, and when they ran the OBDII test I got the following codes...P0303, P0304, P0174, and P0171. Is this bad, very bad, or several grand bad?

[skylolow]

Not sure what each code means. Might beable to do some digging on the internet for it. I want to say P0303 and P0304 is a misfire in the 3rd and 4th cylinder and the other two are lean fuel mixtures. Could be wrong though. Good chance this could just be an error and the after driving a week or so the error goes away.

But generally speaking the increased emissions can be cause by alot of different things. None of it expensive usually. I'd expect your local dealer can resolve your issue for under $500. It can be anything from one of the many O2 sensors, gas cap, fuel pump, bad gas, etc. etc. My suggestion would be drive it for the next week or two and see if it goes away. Its not uncommon that it will just disappear and never come back, chalk it up as a glitch.