check engine light and various codes
 

I was driving today when stopped at a traffic light with my window open noticed a sort of a whistling/air sound. My check engine light came on and I pulled the codes and they were p0171, p0101 and p0102. When my car is in park or neutral and I give it some gas it seems as if the car is going to stall out. Rpm goes down almost all the way and then kinda kicks back in?/??? At one point the RPM went down so much that the little arrow lit up on the dashboard for a quick moment and then shut off. Any suggestions on what this may be? my volvo s40 is a 2002 1.9t and I have about 85000 miles on it?

RE: check engine light and various codes
 

Check your air filter, the air filter box and hoses. Also you can check the mass air sensor.

RE: check engine light and various codes
 

Yes check the Big hoses from the Air box and the intercooler. 2 out of the 3 codes are mass flow codes.
If you hear a Hissing/air noise chances are a hose came off.