Stalls when accelerating in wet weather

I dont use this word much but im Assumeing that YOUR mechanic scanned the computer and checked the coolant sensor or other possible causes,Ive ran across this many times before so bare with me,Have your mechanic try a known good Airflow meter and dont forget to check the main airboot for rips,cracks or tears in the seams,gotta inspect all the areas where it is accordianed for flexibility,another one is moisture penetrating into the distributor cap,got more if ya need them hope this helped let me know have a good day Darrell