Hi everyone,

Before spending an arm and a leg and some more trying to figure out what is going on with my car, I thought I post here and see if anyone of you can venture a guess as to what could be the source of the issue...

I have an 02 X5 3.0i with just a hair over 65000 miles on it. The car is in great shape.

Last week the SES light came on and I plugged my handy OBDII reader into the port and read the code P0171. Two years ago this same thing happened and I realized that I had forgotten to change the air filter for a while. So I did that and the SES light went away.

So, since I had gotten the same "lean" code before, I went ahead and changed the air filter. This time though I changed it with a high flow K&N air filter... the ones you can wash...

anyway, the SES light went away on its own.

A week later (yesterday) I am cruising down the freeway and boom, the SES light came on. I plugged the OBDII again and this time I read two codes... P0174 and P0171. Both "lean" codes saying something like "to lean on bank 1" and "to lean on bank 2".

The question is: Did the K&N filter have something to do with this? I think the MAF is the problem but before spending $450 at the local dealer for a replacement part I wanted to know if anyone had an opinion on what else might be the issue.

The car is running fine by the way. I find that the acceleration isn't as good as it used to be but it is running fine... no stalls or anything else.

Thanks! I really appreciate some help here.