What is next step?

Question

2005 jetta 2.0 BBW

code p101 -- engine runs rough

replaced old MAF with brand new one

with new MAF engine cranks and immediately stalls

air filter is new/clean filter compartment

Answer 1

P0101 MAF sensor circuit / range performance

Unmetered air if it start and stall out you have unmetered air entering the intake from the MAF to the throttle body check for any opening such as rip or tears. It is also a good idea to look at the condition of the timing belt, you can easily remove the cover of the top what you have is a range performance on the MAF, the  timing belt, large unsecured intake leak will take the MAF out of range