Adding my $.02 cents to the most recent P0174 and P0171 thread on the board... I struggled with this for a couple months and finally diagnosed it as improper screws holding down the MAF. Aparently the Delphi (OEM replacement) part in the US comes with new hex screws that are a bit too long and a grade to thin. A shop replaced the factory screws with the new MAF as preventative maintenance. I ruled out the MAF and went chasing a smoke machine to learn I didn't have a leak. I pulled everything apart to inspect later and noticed that neither of the MAF screws would fully tighten and one punched through the pre-throttle duct. I replaced with larger screws (M4 or M6, don't recall for sure) and filled the hole with black silicon. Codes have been gone for over a month now and trim levels are healthy. Wanted to share in hopes it might save somebody else the headache and whiskey I went through trying to fix.
