"I come up too."
Translation:Feljövök én is.
It is not unconstitutional. :) But I would translate it with the present continuous. "I am coming up, too." It happens many times when the preverb is separated. That certain sense of completeness is less emphasized, giving the sense of an action in progress. But it is just that, a sense of it.
You can also say "Jövök fel én is."