I just got a new rig and a fresh install of ps2. When stealthed, I have to unstealth before I can fire my weapons instead of firing the weapon to unstealth. I found this on the ps2 forums and maybe this will help you if you have the same issue (it did resolve my issue):
"To my knowledge no. It should be towards the bottom of your user options ini file.
UserOptions.ini:
[General]
DecloakOnFire=1
AbilityQueueSeconds=1.000000
(this will turn it on)
If your like me, and you wanted to use the manual key to delcoak oldschool that is DecloakOnFire=0
AbilityQueSeconds=1.0 means you can for example hit decloak, and while this is occurring que a grenade toss or something to happen one second later. Again I have mine set to zero because it can cause issues as well. To each their own though it can be helpful when it comes to chaining abilities like activating knives ect. "
