Air Nail Gun not Firing | Nail Gun Air Coming from Trigger

In this video, we fix a Porter Cable Air Nailer that will not fire. It has a hissing sound coming from the trigger.

This is the trigger valve I needed:
https://amzn.to/3U2l8Xq

For Porter Cable 647620-00 Trigger Valve Assembly For Porter Cable N566148 647956-00 641011-00 64762000 FN250C DA250C
Size: 1.6 x 1.2 x 0.8 inches
Package includes: a trigger valve component
Replacement model: 64762000 647956 00 64795600 641011 00 N566148
For Porter Cable N566148 647956-00 641011-00 64762000 FN250C DA250C
Fits the following models: D51256 Type 1 Finish Nailer Kit, D51256 Type 2 Finish Nailer Kit, D51238 Type 1 Brad Nailer Kit, D51430 Type 1 Stapler, D51431 Type 1 Stapler, D51321 Type 1 Coil Roofing Nailer, D51238 Type 2 Nailer, D51256 Type 3 Nailer, D51275 Type 2 Nailer, D51275 Type 3 Nailer, D51430 Type 2 Stapler, D51431 Type 2 Stapler, D51825 3 1/2 Framing Nailer, D51850 3 1/2 Framing Nailer, D51276 15 Gauge Finish Nailer, D51257 16 Gauge Finish Nailer.
Fits D51275 Type 1 Finish Nailer, D51855 Type 1 Coil Framing Nailer, D51321 Type 2 Coil Roofing Nailer, D51822 Type 4 Framing Nailer, D51844 Type 4 Framing Nailer, D51257K Type 1 16 GA Finish Nailer, D51257K Type 2 16 GA Finish Nailer, D51276K (Type 1) 15 Gauge 1" to 2-1/2" Finish Nailer, D51238K (Type 1) 2" 18 Ga Brad Nailer.