KaylaBaby1141

For about 2 months now I have been having issues with my 2001 chevy 1500 at first it will run and drive fine than after so long it acts like it doesn't want to shift or just not getting any gas
most recent freeze frame data below

DTCFRZF P0300
FUELSYS1 OL
FUELSYS2 OL
Load_PCT(%) 17.3
ETC(°F) 73
SHRTFT1(%) 0.0
LONGFT1(%) 0.0
SHRTFT2(%) 0.0
LONGFT2(%) 25.0
Map(inHg) 28.4
RPM( /min) 1083
VSS(MPH) 0.4
MAF(lb/min) 5.590
TP(%) 41.2

chem_man

Well, here goes:
P0300 indicates you have a misfire on one or more cylinders. The misfire count is below the threshold for identifying which cylinder or cylinders is/are misfiring. Common Causes: worn spark plugs, bad spark plugs, bad spark plug wire(s), bad ignition coil(s), bad or dirty fuel injector, weak fuel pump,...

Fuel System 1 & 2 Open Loop - means that the engine is running off of one of the memory tables contained in the PCM and is not receiving/taking date from various sensors such as the Oxygen Sensors.

Closed Loop Fuel System is when the engine reaches a certain operating temperature and the PCM receives/accepts data from the the Oxygen Sensors, the Mass Air Flow (MAF), Manifold Air Pressure (MAP), Intake Air Temperature (IAT), Engine Coolant Temperature (ECT), Throttle Position (TPS) sensors as well as a few others.

ECT(Deg F) 73 means that your Engine Coolant Temperature (ECT) Sensor is telling the PCM that the coolant in your engine is only 73 Deg F. Now, if you engine has only been running for about 1 minute, then this might be normal, low but normal. If the engine has been running for several minutes, then this is likely a bad reading due to a faulty ECT Sensor, which can contribute to the engine running rich as indicated by the LONGFT2 (Long Term Fuel Trim Bank 2) reading of +25%.

LONGFTX and SHRTFTX stands for Long Term Fuel Trim and Short Term Fuel Trim, and X stands for Bank 1 or Bank 2. If the engine is running properly, and all the sensors are providing the PCM with accurate data AND the Fuel System is in Closed Loop, the PCM then calculates the Short Term Fuel Trim (STFT) and Long Term Fuel Trim (LTFT) values for each cylinder bank. The STFT values are an indication of what is happening right now and the moment to moment fuel system changes that are occurring (either adding more fuel to a cylinder or taking away fuel from a cylinder). The LTFT values are an indication of what is happening over a much longer period of time with respect to the fuel system changes.

Ideally, one wants the STFT and LTFT values to be 0%. However in practice, values in the range of -10% to +10% are completely acceptable. Positive FT values indicate that the engine is running LEAN and as such has to have more fuel added in order to keep the proper combustion properties. Negative FT values indicate that the engine is running RICH and that fuel is being withheld in order to keep the proper combustion properties.

Again, FT values between -10% and +10% are fine. When the FT values get and stay below -25% or above +25%, the PCM will set a Diagnostic Test Code (DTC).

Looking at your STFT and LTFT values, it appears that there is something wrong with all of your Oxygen Sensors. Either the sensors themselves are bad or the wiring to the sensors is bad. Have you looked at the voltage readings from the 4 Oxygen sensors?

Now, in summary, I would say that based on your description of how your truck is running and the data you present, your engine is likely running rich which could be from a vacuum leak or a faulty reading from the MAF sensor, MAP sensor or the Throttle Position sensor.
You also likely have a bad ECT sensor that should be replaced.
You also have a problem with the Oxygen Sensors either not being hooked up or not working properly. Why you are seeing a LFTF for Bank 2 and not a STFT is weird.
Your PCM is staying is Open Loop Fuel Status meaning it's relying on preprogrammed instructions for how much gas to use rather than going on data that is generated by the sensors in real time.

If there are no other DTCs present than the P0300, then I would say something is definitely not right because there should be other DTCs present related to the ECT sensor and your O2 sensors.

Next a couple of questions:
1) How long was the engine running when you captured this data?
2) Were you driving or was the truck parked?
3) Are you able to capture real time data for the O2 sensor voltages, Intake Air Temp, and other parameters?
4) Can you measure the fuel pressure?

Good Luck!