In many cases the culprit was, someone pushed the “Sync Dataset” button on Report Style Maintenance. It can take a Job Traveler from 10 seconds to literally 10 minutes. If you have pushed that Button on an Report, you might want to use the Base SSRS Style, with your New Report Data Definition for a quick test.
Anyhow, Epicor writes to the Epicor SSRS Reports Database, you would want to run your Profiler there as well.
Your Options:
- SQL Profiler (lots of youtube videos on it)
- Epicor Performance and Diagnostics Tool - Via Admin Console you can Enable SQL Logging and then you can just read the log files in ServerLog.txt or use Epicor PDT to parse it for easier reading.
For more information you can download the Epicor Performance Tuning Guide Technical Reference from EpicWeb, it has a whole section on Server Logs, Profiling, Tracing.