I am working on a 2000 Ford Taurus with a 3.0L that has 215K on it, It has several codes that came up, the first is a P0191-Fuel Rail pressure sensor circuit range/performance, P1237-Fuel pump secondary circuit fault, and a P0300 Random/Multiple misfire fault that probably came along with the rough running engine from the injector circuit fault. I checked the fuel pressure and I am getting 42psi and it should be 50 to 56psi with the engine running. I have replaced the fuel pump and filter, but got no change in results. Is it possible the regulator is failing? Or can someone tell me what other components I can test or replace to correct the symptom.

P0191 OBD II Trouble Code Fuel Rail Pressure Sensor Circuit Range...

P0191 Ford Fuel Rail Pressure Sensor Circuit Range Performance

SENSOR 1 ??????????? There is no sensor one involved here . After replacing all those parts an not fixing the problem ,suggest you take it to a qualified repair shop. The proper thing to do would be to do the diagnostic's for code P0191 . Do you know what a factory diagnostic flow chart is ? How to test electrical circuits ?

Anon, Trouble code P0191, You may need a good tech. with scan tool to read and test system.

• Fuel Rail Pressure Sensor Circuit Range/Performance,computer see's signal from the Fuel Rail Pressure Sensor and/or its circuit is sending erratic readings, indicating a fuel pressure condition that is abnormal. Problems could be out of gas, leaking fuel, faulty fuel pressure sensor, bad wire or plug in circuit,fuel pressure regulator, the fuel pump could be faulty also. Check the attached links,instruction and guides, Good luck
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P0191 OBD II Trouble Code

P0191 Fuel Rail Pressure Sensor Circuit Range Performance

RAV4 2001 Trouble Code p0191 probable solution Toyota Nation Forum Toyota...

code P0191 2007 Toyota Google Search

first change gaz filter...
Replace fps(fuel pressure sensor)

Possible causes
- Low or no fuel
- High fuel pressure
- Low fuel pressure
- Faulty Rail Pressure (FRP) Sensor
- FRP harness is open or shorted
- FRP circuit poor electrical connection
- Faulty Fuel Pump
- Vacuum leaks
P0191 Ford - Fuel Rail Pressure Sensor Circuit Range/Performance P0191 Ford Description
The Fuel Rail Pressure (FRP) sensor is a diaphragm strain gauge device in which resistance changes with pressure. The electrical resistance of a strain gauge increases as pressure increases, and the resistance decreases as the pressure decreases. The varying resistance affects the voltage drop across the sensor terminals and provides electrical signal to the Powertrain Control Module (PCM) corresponding to pressure.
Strain gauge type sensors are consider passive sensors. A passive sensor is connected to a voltage divider network so that varying the resistance of the passive sensor causes a variation in total current flow.
Voltage that is dropped across a fixed resistor in series with the sensor resistor determines the voltage signal at the PCM. This voltage signal is equal to the reference voltage minus the voltage drop across the fixed resistor.
The FRP sensor measures the pressure of the fuel near the fuel injectors. This signal is used by the PCM to adjust the fuel injector pulse width and meter fuel to each combustion cylinder.

You need to have the fuel pressure checked, to see if the fuel pump or fuel filter may have a problem. The code is for the Fuel Rail Pressure sensor, and the reading from it is out of range.

2004 Ford 150 5 4L Stall No Start P0191 Fuel Rail Psi Sensor P1233 Fuel...

That is P0191 not o.
P0191 FORD - Fuel Rail Pressure Sensor Circuit Range/Performance

Possible causes- High fuel pressure
- Low fuel pressure
- Damaged FRP sensor
- Excessive resistance in the circuit
- Low or no fuel
- Wiring harness connector of the fuel pressure sensor
- Fuel Rail Pressure Sensor
-

P0191 FORD - Fuel Rail Pressure Sensor Circuit Range/Performancehttp://engine-codes.com/p0191_ford.htmlForum CodePossible causes- High fuel pressure
- Low fuel pressure
- Damaged FRP sensor
- Excessive resistance in the circuit
- Low or no fuel
- Wiring harness connector of the fuel pressure sensor
- Fuel Rail Pressure Sensor
- Fuel
- Vacuum leaks

Diagnostic Test code (DTC) P0191 has a generic description which reads "Fuel Rail Pressure (FRP)Sensor Circuit Performance"

This code sets when the Powertrain Control Module (PCM) is monitoring the fuel rail pressure sensor signal under certain driving conditions. The FRP sensor varies return voltage to the PCM to indicate the fuel pressure at the fuel rail on the engine. DTC P0191 sets when the voltage received from the FRP is above or below the expected "range" or "threshold".

The possible causes of this code are:

> High fuel pressure
> Low fuel pressure
> Damaged Fuel Rail Pressure Sensor (FRP)
> Excessive resistance in FRP circuits.
> Low or no fuel

With all of that said, I would recommend that if you have more than 30,000 miles on your current fuel filter, I would try that FIRST. Replace the filter and clear the code. If the code returns, then diagnostics will need to be performed to find the actual cause.