Vehicle has been well maintained - fuel filter at 60K miles, spark plugs (003 159 94 03) at 5 years (52k miles), air filter at 30K and 60K miles, engine lubrication every 7.5 K miles, with synthetic oil and fleece oil filter.

Air mass sensor has not been replaced... dealer has repeatedly stated that it is not faulty. No fault codes have ever been present; have no idea what the real time data shows.

Since 2006, has a newer software version been issued?

The vehicle has had this intermittent problem since new, which persists despite the two software updates.