Have you checked your air filter?
Back when my airbox had a hole in the bottom as did the bottom of my UNI filter, I had the same problem. It would choke down and stall out, then re-start after a few minutes. I found that the bottom 3rd of my air filter was getting washed out.
I bought a new UNI filter, and never cut holes in the bottom, so it covers the hole in the bottom of the airbox. Haven't had a problem since. (In the rain).
