Mine looks cracked and brittle but It doesn't do it in warm temps. on 2000 Pontiac Grand Am

In cold under 10 degree mornings my car runs fine on highway then after I get off the highway the rpms drop and drop too low and sometimes stalls but mainly rough idle. Any ideas?

1 answer 5 comments
What looks "cracked and brittle"? Have it scanned for codes!
The hose coming from the MAP sensor. And yes and all I got was a emissions malfunction code. I believe it was p0440
The most common cause for that code is a gas cap problem. Replace the map hose.
Would the MAP hose cause it to stall only after the car comes off highway or have a low idle?
It sure can.
Just fixed the vaccume leak haven't drove it much yet.