Using this fuel pressure sensor kit is quite straightforward. First, make sure your Subaru vehicle is one of the compatible models (2007 - 2021 STI, 2008 - 2021 WRX, or 2007 - 2012 Legacy GT) and has a 5 - Pin TGV Plug. Select the fuel line fitting you need, either 5/16 or - 6 AN. Then, install the Honeywell OEM - quality 100PSI fuel pressure sensor using the included fuel line adapter. Apply the Loctite 545 sealant tube during installation to prevent leaks. Connect the custom - designed wiring harness properly. Remember, you can't run the Secondary Injection Controller, Flex Fuel Sensor, and this kit all at once. You can only use two of them at most, unless you wire the SIC for power only with a custom harness. For maintenance, check the sensor and connections regularly for any signs of wear or damage. If you notice any issues with fuel pressure monitoring, it might be time to inspect the kit components.