Listening in the exhaust pipe will show a problem on the exhaust side.
Either way, the " class="glossary Link "cylinder head must be removed.
But this particular problem is with a computer trouble code P0300. For a particular cylinder, the code would be P0301, P0302, P0303 or P0304, as the last number refers to which cylinder is misfiring.
On a scan tool we can actually watch the cylinder misfire.
This problem can be caused by a faulty " class="glossary Link "spark plug, malfunctioning ignition coil or ignition module, a plugged or restricted fuel injector or an internal mechanical problem.
The problem we are seeing with this engine is the misfire on a warmed up motor, only at idle.
That is done by removing the spark plugs, disabling the fuel injector and ignition systems, and cranking the motor over with the tool installed. First, how high the pressure jumps on the first revolution, and then what is the highest reading after a few seconds of cranking.
Cylinders are compared to each other looking at both these readings.Normally we mechanics would first look for a " class="glossary Link "vacuum leak.This would cause the problem at idle any any motor.In this case, the compression on one cylinder is a little low.Squirting a little motor oil in the cylinder and running the test again shows no improvement.But since we are using a scan tool to watch live data stream, we know which to look closely at. Low total compression can be caused by worn " class="glossary Link "rings, incorrect valve timing, or valve and seat problems.