I took my car in for service and, for some odd reason, the guy replace this particular vacuum hose with a new hose but without the one way check valve. Is my car going to explode now?



This is what I am referring to..I took that picture before and had the check valve...but now it's missing.

 

It's not a check valve, it's a filter. It ensures that no fuel/oil deposits find their way to the MAP sensor. I would suggest getting it back from the guy who serviced the car.

-Rob