On top of engine you will see a metal line that feeds fuel injectors that is your fuel rail it will go around to each injector on that line you will see a fitting where you attach a pressure guage
With a fuel pressure gauge connected to the fuel rail.
To check the fuel pressure on a 2001 Kia Optima, you should get a fuel pressure test port. You can purchase one at the local auto parts store in most cases.
To test the fuel pressure on a 2001 Toyota Highlander, you'll need a fuel pressure gauge. First, locate the fuel pressure test port on the fuel rail and remove the cap. Connect the gauge to the port and turn the ignition to the "ON" position without starting the engine to check the pressure reading, which should be within the specified range (around 30-40 psi). If the pressure is too low or too high, it may indicate a problem with the fuel pump or fuel pressure regulator.
The fuel pressure relief valve is located Under the Plastic cover on the fuel rail.
Run a fuel pressure test with a fuel pressure gauge connected to the fuel rail.
Fuel pressure test at the fuel rail.
Your losing spark or fuel. I would start with replacing the fuel filter. If it still dies do a fuel pressure test, it may have a failing fuel pump.
With a fuel pressure test at the fuel rail.
A fuel pressure test will help determine the condition of the fuel pump and fuel pressure regulator provided the fuel pump electrical circuit, fuse and relay check okay.
Probably the fuel pump is on its way out. Have a fuel pressure test done.
Fuel pump pressure test.
Pressure test ?? Cooling system? A/C? Fuel Pressure? Compression?