I was wondering if you could give me your opinion about a car issue I am
having. My 1997 E320 with 95k, is having a PO170 error code. It first came
on a couple weeks ago and I had my mechanic look at it.

PO170 corresponds to "Fuel Trim 1" and there are a list of things this could
be. For some reason Mechanic A doesn't think it's the Mass Air Flow sensor
but Mechanic B does. I had a second opinion. I even brought it to AutoZone
to have the code read... and sure enough it reads PO170 and he thought it
could be an O2 sensor.

I've done a little research and from what I understand PO170 can be the MAF
but usually it has two codes PO170 and PO173. My car is not driving
abnormally. I can merge in and out of traffic and I can accelerate smoothly.
Maybe my car is supposed to be more responsive and powerful? I don't know.

The second mechanic I went to practically specializes in Mercedes and his
sister-in-law works with me. He mentioned that in his experience PO170 is
the MAF. But, I was very concerned when it only took him 5 minutes to come
to that conclusion.

Before I go to the Stdealer, I was wondering if you had any experience with
this. I am frustrated with this situation because I am getting 3 different
answers from 3 different good sources.

I posted this question for my nephew it is his car. Any help would be
appreciated