Duramax Issues and Answers

I have a 2001 2500HD Duramax. I was wondering what would be wrong if the truck surges at an idle only when the engine is cold. It usually will not surge if the outside temp is above 70 degrees. Anything colder than 70 degrees it surges a couple hundred rpms very aggressively and the check engine light will come on. The code is low fuel pressure (P0089 I think). If I kick the RPM up to 1200 it will stop surging. My local dealer thought maybe the mass air sensor is faulty. I was wondering what is your take on it. Thanks, Kevin.