the motor speed is sufficient for the position of the CKP sensor(Crankshaft position sensor) to change, the ECM (Engine Control module) determines that there is a misfire. The diagnostic codeP0305 indicates that it has been detected that one of the cylinders of the motor is not activated correctly, in this case it is specifically cylinder number 5.
A code P0305 can be caused by one or more of the following problems:
Lack of fuel.
A spark plug could be defective.
The coil may be in poor condition.
One or both O2 Oxygen Sensors may be failing.
Fuel injector may be defective.
Exhaust valve may be burned.
The catalytic converter could be defective.
Possible solutions of the DTC code P0305 Generic
To fix the DTC code P0305 you can check the following components:
In the event that the motor presents instability, you can check all the wiring and its respective connectors that lead to the cylinders, ie the spark plugs. Take into account that all these ignition components have a life time and that it is necessary to change them, because they wear out due to their time of use. You can change spark plugs, these wires, distributor cap and the rotor in case you have it.
Verify that the coil works correctly, change it if necessary.
Check the catalytic converter, perceiving a smell in the exhaust pipe indicates its bad condition, you can repair or replace it if necessary.