JSurovik

I have a 2015 GMC Canyon. Each time I fill up my gas tank, my truck is very hard to start. Then when it finally does start it may die & I’ll have to restart it. It’s not bad gas because I can go to any station & it happens. The OnStar people did a diagnostic test & said it’s in the emissions system. What could it be? Anyone else have this problem? Any help would be appreciated!!