That switch is quite old! - Have you checked the health of it?
Would you be able to post the output of the following into a file?
sh process cpu sorted/history
sh memory summary
sh int x/x controllers
show interface | include line|\/sec
show ip interface | in switch
sh version | in Ba
sh spanning-tree root
sh spanning-tree summary
show spanning-tree detail | in ieee|root|top|link|bpdu
Thanks for the output
im traveling at present so kind of hard to read that output - however may I suggest a few tweaks?
on the L3 core
1) my sure that switch is the stp root for all vlans (even vlan 1)
2) enable stp loop-guard uplinkfast globally on all switches And stp portfast-bpduguard on all access ports
3) enable fast switching on the l3 interfaces ( ip route-cache)