We recently noticed the app pool has been restarting every 5-30 minutes. We're not sure how long this has been going on. It was only noticed because the site gets slow right after a restart. I can't get good logging to tell me what the cause is. Application_End does not seem to be hit when this happens. The system event viewer just tells the the app pool restarted. It usually says the job limit has been exceeded, but I have no limit set in my IIS. 

Application pool 'azcourts.gov(domain)(2.0)(pool)' exceeded its job limit settings.

A process serving application pool 'dev.azcourts.gov(domain)(2.0)(pool)' suffered a fatal communication error with the World Wide Web Publishing Service. The process id was '16100'. The data field contains the error number. 

I thought it might be a stack overflow somewhere in some custom modules I made recently, so I temporarily took them off the site. It kept happening. I thought it may be some scheduled task so I disabled the scheduler completely. It kept happening.
I've checked the /bin folder, Global.asax, web.config and App_Code folders and none of them are being changed that frequently. Does a change in the Desktop Modules folders have any affect?

I've looked in the Admin-Event viewer and there is no common thing that happens right before a restart.
I'm out of ideas for what is causing this. Any hints on where to look next?