The problem you're having is the fuel pressure sensor, you need to verified the the fuel pressure reading is correct (Check that the signal is within its permitted range. The normal value is 480 ± 5 kPa when idling.) also check the fuel pump module's conector for rust. its located under the car on the right rear and it can get water/rust. if you have farther question call 909-749-6182
the the price for the fuel presure sensor is $136.76
284: ECM-2600 Fuel pressure sensor. Signal too low, B5244S4
Diagnostic trouble code (DTC) information ECM-2600
Condition
The engine control module (ECM) checks the signal from the fuel pressure sensor.
The diagnostic trouble code (DTC) is stored if the engine control module (ECM) registers a fault in the signal from the fuel pressure sensor.
The diagnostic trouble code (DTC) can be diagnosed when the ignition is switched on.
Substitute value
The fuel pressure is set to a constant.
The control signal to the fuel pump (FP) control module is set to a calculated value.
Possible source
Signal too high
Short-circuit to supply voltage in the signal cable.
Open circuit on signal cable.
Damaged fuel pressure sensor.
Signal too low
The signal cable is short-circuited to ground.
Damaged fuel pressure sensor.
Fault symptom[s]
Malfunction indicator light (MIL), on
Engine misfires
Notes: the p code is you provided is missing one number, i think its p0191?
