Auto Parts: codes p0171 and p0174, vacuum leak, bmw 330ci

Question
I own a 2001 bmw 330ci. My service engine soon light came on recently and wanted to know what the problem is. I've looked online at forums for codes p0171 and p0174, it varies. Seems most say either vacuum leak or maf. How would I check? I noticed it came on a day after I pushed the engine a little bit on the highway. redlined it a little, if that triggered the problem. Your response is greatly appreciated.

Pete

Answer
The codes in which you are recieving are both Bank's 1&2 running lean. I would start by checking that the oil fill cap is properly installed and is in well working order, I have seen in many instances this causing a check engine light with the same codes. As for the MAF sensor, It could be a possibility, Although during its failure you would notice a change in pickup and idle. The 2001 E49's are very consistent with needing the MAF Recoded/Reinitialized, Check with a BMW Dealership to see if your specific model falls into this category. Another possibility would be O2 sensor's, You're vehicle is equipped with Heated Sensors, You can check the sensor's by testing them for voltage while your ignition is in the RUN position without the engine running. All of these are reminiscent of the stated codes. I hope my answers are useful to you. If your problem should persist please do not hesitate to say so. i would be more then happy to purse this issue further...

Mike Anthony.