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P0300 is a random miss fire , a vacuum leak can cause this as well as low fuel pressure ! weak fuel pump , clogged fuel filter !
DTC P0171: Fuel Trim System Lean Bank 1
DTC P0174: Fuel Trim System Lean Bank 2 These two codes are saying the PCM - engine computer is see a lean condition .
DTC P0191: Fuel Rail Pressure (FRP) Sensor Performance
The fuel pressure sensor is located on the fuel line. The fuel pressure sensor monitors the fuel pressure in the fuel line. The fuel pump flow control module (FPCM) monitors the voltage signal from the fuel pressure sensor.
You don't say what make , model an year vehicle ! These are for GM vehicles , yours could mean something else . Except the first three , those are genaric codes , same for all makes ! So can't say what this codes are P2097, and P2099 ! Can't mean this P2097 - Post Catalyst Fuel Trim System Too Rich Bank 1
P2099 - Post Catalyst Fuel Trim System Too Rich Bank 2
DTC P2097 Post Catalyst Fuel Trim System High Limit Bank 1
The wide band heated oxygen sensor (HO2S) measures the amount of oxygen in the exhaust system and provides more information than the switching style HO2S. The wide band sensor consists of an oxygen sensing cell, an oxygen pumping cell, and a heater. The exhaust gas sample passes through a diffusion gap between the sensing cell and the pumping cell. The engine control module (ECM) supplies a voltage to the HO2S and uses this voltage as a reference to the amount of oxygen in the exhaust system. An electronic circuit within the ECM controls the pump current through the oxygen pumping cell in order to maintain a constant voltage in the oxygen sensing cell. The ECM monitors the voltage variation in the sensing cell and attempts to keep the voltage constant by increasing or decreasing the amount of current flow, or oxygen ion flow, to the pumping cell. By measuring the amount of current required to maintain the voltage in the sensing cell, the ECM can determine the concentration of oxygen in the exhaust. The HO2S voltage is displayed as a lambda value. A lambda value of 1 is equal to a stoichiometric air fuel ratio of 14.7:1. Under normal operating conditions, the lambda value will remain around 1. When the fuel system is lean, the oxygen level will be high and the lambda signal will be high or more than 1. When the fuel system is rich, the oxygen level will be low, and the lambda signal will be low or less than 1. The ECM uses this information to maintain the correct air/fuel ratio.
Fuel trim biasing is used by the ECM to keep the post catalyst HO2S voltage within a range of 580-665 mV as possible. This allows optimal catalyst efficiency under light load conditions, such as at idle or a steady cruise. The ECM constantly monitors how lean or rich the fuel trim bias is commanded. If the ECM detects that the fuel trim bias is commanded rich for more than a calibrated amount, DTC P2097 or P2099 sets.
P2097 code has two fault locations. 1) post catalytic converter fuel trim (FT), bank 1 - too rich. possible cause Catalytic converter. 2) Heated oxygen sensor (HO2S) 1,bank 1 range/ performance- circuit low. if it's running fine. probably just need to put an oxygen sensor in it.
Here is some general information to get you started...
(I am quoting directly from several PDF sources, Googled).
STFT B1 = Short Term Fuel Trim Bank 1. This is the fuel correction percentage being used by the closed loop fuel strategy for Bank 1 (if a V style engine or for all cylinders if an inline engine). If the fuel system is in open loop, this number will be reported as 0%
Fuel trim refers to the feedback compensation value compared against the basic injection time. Fuel trim includes short–term fuel trim and long–term fuel trim.
Short–term fuel trim is the short–term fuel compensation used to maintain the air–fuel ratio at its ideal theoretical value. The signal from the heated oxygen sensor indicates whether the air–fuel ratio is RICH or LEAN compared to the ideal theoretical value, triggering a reduction in fuel volume if the air–fuel ratio is rich, and an increase in fuel volume if it is lean.
Long–term fuel trim is overall fuel compensation carried out long–term to compensate for continual deviation of the short–term fuel trim form the central value due to individual engine differences, wear over time and changes in the usage environment.
If both the short–term fuel trim and long–term fuel trim are LEAN or RICH beyond a certain value, it is detected as a malfunction and the check engine warning (CHK ENG) lights up.
If the total of the short–term fuel trim value and long–term fuel trim value is within ± 25 %, the system is functioning normally.
P0171 indicates a lean condition. The most common cause of this is a defective mass air flow sensor. Also check if any vacuum leaks.Replace MAf sensor,if cleaning the MAF does not help. OBD II P0172 Fuel System Too Rich (Bank 1).P0172 - System Too Rich (Bank 1) Essentially this DTC means that an oxygen sensor in bank 1 detected a rich condition. When the code says that the Fuel System is "too rich," it means that the computer has been subtracting more and more fuel, which is called Long Term Fuel Trim. Ideally, the Long Term Fuel Trim should be close to 1 to 2 percent. When a code P0172 is set, it means that the Fuel Trim is anywhere from -15 percent to as low as -30 percent compensated. When this happens, the computer knows that there is an improper condition in the control of the Fuel System.
actually there are 4 sensors. one on each exhaust manifold and then as you said one prior and aft the catalytic convertor. this is saying it is reading too rich a reading. check the condition of your spark plugs. you need to pin point the reason. chances are it is not the o2 sensor. happy holidays