Thanks for the post Larryg,

I can't find much information on this brad nailer anywhere, but I found a photo and it looks like a pretty typical nailer. Porter Cable does make a similar model so that may be true.

Without seeing it or properly diagnosing it I can only give you some general advice, but it sounds like a trigger issue to me.

Since there is not much information on this tool so I can't really see what the setup is, but from my experience it seems to me the first thing to check would be the trigger and safety assembly, this is what actuates the tool to "fire" or "cycle". If there are multiple firings or cycles air pressure must pass through the trigger valve for this to happen. The tool should be disassembled and thoroughly cleaned, check all o-rings,seals and hardware for wear or damage and replace as necessary. When reassembling lubricate all seals, o-rings and moving parts with good quality lubricant.
Take a look at the trigger valve and the o-ring in (and around) the valve, first. I think you'll find that a good cleaning (and lubrication) will fix the problem.

- MTR

Sounds good, and let us know what you find when you inspect it further!

- MTR

I still think there is a trigger valve issue, honestly. - Air pressure must pass through the trigger valve into the port to pressurize the tool so that it will fire. If it is firing multiple times then the trigger valve is allowing air pressure to flow for some reason. My first guess is that something went wrong with the installation. I'm not saying it certainly is installed incorrectly, but I would certainly remove it to confirm. Make sure all of the o-rings are lubricated very well and weren't damaged when the trigger valve was installed. Also insert a few drops of pneumatic tool oil (if you haven't already).

- MTR