Okay, the P0300 means there are random cylinders misfiring, not any one at specific time. But this P0128 might be the cause for the other 2 codes. This means the engine is not reaching operating temperature, and even though you have a short drive to work it should reach the set limit of 167 degrees F. The P0172 is an engine running rich code for Bank 2. It's running so rich that the engine computer's (ECM) fuel trim is below -17 percent, that's an extreme amount. These conditions will ruin the Catalytic Converter if they haven't already. So, I think you have multiple problems happening. The thermostat might be stuck open keeping the engine from warming up. And for the rich running condition, it can be a few different components. Since this vehicle is a V6, it has 2 banks. Bank 2 is the one running rich, there may be an oxygen sensor on that side of the engine that has failed and is sending a faulty signal to the ECM, if there are Catalytic Converters for each side and the bank 2 Converter has failed it can cause a rich signal, a Evap system that failed and is drawing raw fuel through the Evap Purge valve. Or leaking fuel injectors. Those are some things that can cause a rich running condition.
I put an arrow going to the Purge Valve, you can check it for any liquid fuel in it or the line coming to it. The purge valve is only to pull fuel vapors from the gas tank so they can be burned in the engine, Sometimes the Charcoal canister fails and gets filled with liquid gas instead of just vapors and they end up in the that vapor line. But the rest of the system will need to be looked at to determine the rich running condition. The cylinder misfire code will clear up after these issues are taken care of, it will save you in the long run.
You're going to have to get the low temperature issue looked at, most likely you need a new thermostat. Here are some guides below to give you an idea of how these components work:
https://www.2carpros.com/articles/how-an-engine-thermostat-works
https://www.2carpros.com/articles/replace-thermostat
https://www.2carpros.com/articles/engine-misfires-or-runs-rough
https://www.2carpros.com/articles/how-an-oxygen-sensor-works
Jan 25, 2023 at 8:51 AM