Code P0300

Welcome to 2CarPros.

Many things can cause a random misfire. Is the P0300 the only code you get? If so, have you confirmed fuel pressure to be within spec? Also, have you checked for engine vacuum leaks?

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

If you haven't done that, I would start there. Also, keep in mind that fuel pressure ( too high or low) can cause this. Here are the manufacturer's specs for pressure.

Fuel Pressure (Key ON, Engine OFF) .................... 380-427 kPa (55-62 psi)

Check that and let me know what you find. If you need a gauge, most parts stores will lend or rent one to you.

Take care,
Joe

Welcome to 2CarPros.

Why was that suggestion made? A relearn is done after the sensor is replaced and I don't believe even replacing one on this vehicle calls for a relearn. Here are the directions for replacement of the crankshaft position sensor. Note at the end is where it indicates a relearn and none is mentioned.

As far as the crank sensor, here are a few links to help. The first explains what it does, the second explains symptoms, and the third shows in general how one is replaced.

https://www.2carpros.com/articles/how-a-crank-shaft-angle-sensor-works

https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

https://www.2carpros.com/articles/crankshaft-angle-sensor-replacement

Here are the directions specific to your vehicle:
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CRANKSHAFT POSITION (CKP) SENSOR REPLACEMENT
Crankshaft Position Sensor Replacement

Removal Procedure

Caution: Refer to Battery Disconnect Caution in Service Precautions.

pic 1

1. Disconnect the negative battery cable.
2. Disconnect the crankshaft position (CKP) sensor electrical connector.

pic 2

3. Remove the CKP sensor bolt.
4. Remove the CKP sensor.

Installation Procedure

Notice: Refer to Fastener Notice in Service Precautions.

pic 3

1. Install the CKP sensor with the bolt.
Tighten
Tighten the CKP sensor bolt to 6.5 Nm (58 lb in).

pic 4

2. Connect the CKP sensor electrical connector.
3. Connect the negative battery cable.

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I'm not saying it couldn't be the sensor, but since it got worse since it was repaired, I would start by checking to see if maybe something like a vacuum line was left off or something wasn't plugged in.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Let me know if this helps or if you have other questions.

Take care,
joe

Hello,

Direct Trouble Code (DTC) P0300 is the DTC for a Random/Multiple Misfire. In the diagrams down below I have included the factory diagnostic troubleshooting guide for DTC P0300. I have also included the fuel pressure so you can check that as well. Another thing to consider, believe it or not, is the Engine Coolant Temperature Sensor (ECT), as this will effect the engine ignition timing, retarding it as the temperature goes up to keep the engine away from detonation. Also inspect the intake air duct, vacuum and EVAP lines for leaks, and especially around the intake manifold for vacuum leaks. This will also make your vehicle run bad. Also double check that the correct fuel injectors were installed. Please go through the guide and get back to us with what you able to find out.

Thanks,
Alex
2CarPros