Just got back from there a couple weeks ago. We went to
one place for fish tacos and I'll let you know where we went.
The vallarta-info.com site has a page for street food stands in
PV with visitor ratings. We visited the street stand said
to have the best fish tacos in town. Great food, my wife and
I loved the tacos there.
Go to the link below and scroll down to Marisma's taco stand. There
will be a map in here too. This stand had about 6 people running it,
looked very clean.