I bought vacuum sealed kielbasa yesterday about 6:30 pm. It must have fallen out of the bag in my very hot car and I didn't notice until about 11:45 the next day...Is it still good?
Sounds like you're going to need some new kielbasa.
Kielbasa isn't fermented, and needs to be refrigerated to stay good. Vacuum sealing reduces the oxygen in the package, slowing down oxidation and inhibiting the growth of some types of bacteria when combined with refrigeration, but that kielbasa won't stand a chance in a hot car.
Time to throw it out.
Even a salted, preserved, and sealed sausage will not survive. The bacteria will begin to multiply rapidly after 30 minutes of sitting out of the fridge.
Perishable food sitting out for longer than 30 minutes is a risk to eat, even when it was frozen. Some food might last 1 hour.
I completed a food safety course with exemplary scores I might add.