Getting p0193 code for my 2005 ford freestar se

P0193 is "Fuel Rail Pressure Sensor Circuit High Input"
Meaning: Car's computer is reading input voltage from the FRP (Fuel Rail Pressure) sensor as
voltage out of the acceptable range, because the voltage is too above the acceptable range.

assuming you are running gasoline...

check for fuel in the vacuum hose of the FRP sensor after running engine at idle for 2 minutes. if not, check fuel pressure. Check fuel pressure by connecting a fuel pressure gauge to the Schrader
connector on the fuel rail, which you will find under a small (black, usually) plastic protective cap.

If the fuel pressure is indeed too high, your fuel pressure regulator has gone bad.

if fuel pressure is good, check voltage between Sensor connector Vref (Pin#3 LB (light blue)) and
Signal Return (Pin#4 GY/RD (gray/red)), which should be 4.0V-5.5V with key ON.
The acceptable voltage range from the FRP sensor to the car's computer is 4.0-5.5 volts.
What the P0193 code is saying is that the voltage from the FRP sensor is over 5.5 volts,
and therefore it's "High Input."

If voltage from the FRP sensor is bad (out of range high, presumably), then replace the FRP
sensor and reset the OBD-II code.

If the voltage output from the FRP sensor is also good, the car's computer is kaflooey, so
you'd need to replace the car computer (which is costly), so replace the car's computer as a
last resort.

This code will come If you even forget to put your fuel cap after putting gas.... and it will go away after 3-4 cold start (min 8hours between two starts).