I think its the maf. I bought generic one and im having this problem.
I have 3 bad sensors now.
U said urself when u disconnect maf or map it works.
For some reason i have the same problem when the car gets hot.
Get only oem maf.
Btw. Ur mechanic if he checked the code he could offer u to check the maf before replacing the gasket. Im assuming u paid almost $500.
When the car dies from coolant leak on the high way it wouldn't turn on (had that too)
Try a new maf.