Had a 2001 Jetta tdi that was very hard on mass airflow sensors. Didn't find it economical to drive due to high maintenance costs, or dependable, and traded it.
DaveL
ps Great website for those interested--
www.tdiclub.com I wonder with ultra low sulfur gas out now, would you had less problem
My son has 2006 Jetta TDI for a year now, no problems with the engine