I work on Fremont Street between Market and Mission...joined the firm about a month ago and have been experiencing the same issues that are being discussed here. I have no idea to run a diagnostics test but I can affirm that there is a massive issue with the service in this area.

I walk home towards Russian Hill everyday and it's not until I cross over Pine Street that any of my service appears to come back to a reasonable speed. Wanted to chime in say that I have similar issues...