Maybe not projectile vomit but they absolutely could reverse peristalsis just like any vertebrate. Giraffes chew their cud while upright after all. Peristalsis is agnostic to how high it's pumping, since there is no functional loss in strength.
What I'm describing isn't actual vomiting either, but more like regurgitating. Rodents can do that, though horses can't (because they can't even belch, they've got a one way valve).
Ruminants like sheep and giraffes also don't externally vomit but they do internally vomit which makes stuff change chambers in their stomach.