This is an issue I come across once in a while and since I am not a COM expert by any means I actually had to check in with our COM guys to see what was going on in this case, and as it turned out (this is embarrassing:)) I had already written about the root cause of this issue before (here). So what I am learning from this is that perhaps I should at least check my blog before asking questions:)
Problem description
Intermittently the application will stall, so all requests will hang until they run an IIS Reset. At this point the CPU usage for the process is very low.
Gathering memory dumps
A memory dump was gathered using Go to the complete details ...