a new used car

I bought a car today from a co-worker, it's a '90 chevy cavalier rs.

There was some trouble driving it home, I think it may just need some more work.

what happens is that it stalls when it comes to a stop after being on the freeway, the guy I bought it from says that it might be the transmission, it isn't downshifting from freeway speeds.

If this problem persists I may need to sell it back to him.