P0301 Introduction

The P0301 is not too different than the P0300 trouble code, the only difference being that this particular code is only triggered by an improper firing in the cylinder #1. Thus the name Cylinder #1 Misfire. This time is neither random nor multiple so the driver’s or the mechanic’s attention will be directed towards this cylinder.



The symptoms are also the same: the computer reports the malfunction and illuminates the Check Engine Light which in most of the cases is also the only symptom recorded by the driver, hard engine start, the engine jerks when the driver accelerates, hesitant engine, fuel economy decrease, power is lacking, or rough idling.

What Leads to P0301?

It’s easy to say that the cylinder #1 is not firing properly however there are a multitude of malfunctions that case the triggering of the P0301 trouble code:

  • One very popular trigger for this code is found in the Ignition System.
  • Vacuum leakage.
  • Broken oxygen sensor.
  • Not enough fuel pressure.
  • Camshaft Sensor defection.
  • Some defection in the EGR system.
  • Improper ignition timing.
  • Broken vehicle computer, which is handled through a rapid replacement.

P0301 Indicated Solutions

The obvious solution in the case of any trouble code is to reset the respective code, drive for another day and pray that the code doesn’t make its comeback. Who knows, you might get lucky and there was only a problem with the computer.

Check for wear signs in the following components: ignition wires, spark plug, ignition coil, and distributor cap together with the rotor. But what are the signs for the mechanic or the driver to pay close attention to? To see if these pieces are not worn out they should have a sandy color. Plus the presence of factors like corrosion or arcing signs is an indicator that the respective component(s) must be replaced until it doesn’t stop the combustion process completely.

If you have the proper equipment like a scan tool, make sure that the voltage for the cylinder #1 is situated around 8-10 kilovolts. The clue that leads to the conclusion that the catalytic converter must be replaced is the smell of rotten eggs in the exhaust. That one cannot be missed for sure.

If the problem appears when you accelerate and you feel the engine jerking then the malfunction might be located in the overdrive gear or the Lockup Torque Converter might present a chattering clutch. On the other hand, if the problem appears during deceleration then the causes might be: the transmission is shifting hard, sticking brake pads, or rotors are badly warped.

Even if you as a driver wouldn’t be the one handling the repairing of whatever is causing the triggering of the P0301 code, these pieces of information are very useful because you would be able to know exactly what your mechanic is doing and if he is executing a professional job. The diagnostic is the most important part, just as it is with medical cases.

If the problem is wrongly identified then you might end up changing the entire engine so make sure that your mechanic sets the right cause for the P0301 code and for more information read also the post on the P0300 code.

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