The P0304 code means that cylinder #4 is misfiring or is randomly misfiring. The P0350 code means that the Powertrain Control Model (PCM) has detected a problem with the primary or secondary circuit of one or multiple ignition coils or ignition coil packs in your engine.
The P0304 code is a serious engine issue that requires immediate attention. A misfire is the absence of a full combustion event on a given cylinder as expected.
***Here are some possible causes of a P0304 code:***
* A faulty ignition coil, spark plug, or wire
* Loose fitting electrical connectors
* Broken or disconnected vacuum hoses
* The engine is dirty or has low oil pressure
***Here are some possible causes of a P0350 code:***
* A problem with the electrical circuit
* Damaged or loose connection of the spark plug wires
* A faulty PCM
The most common symptom of a misfiring engine is a loss of power. The engine may also run rough, be difficult to start, or stall completely.
***Here are some repairs that can fix a P0304 code:***
* Replace the spark plugs
* Replace the cap and rotor, coil pack, or plug wires
* Inspect the wires around the spark plugs for damage and loose connections
* Replace a faulty fuel injector
* Replace a worn ignition wire or a bad coil
* Repair engine mechanical issues
* Fix air leaks
* Repair fueling faults
* The P0350 code indicates that the Powertrain Control Module (PCM) has detected a malfunction in the circuit of one or more of the engine's ignition coils. The code is set when the Engine Control Module (ECM) does not receive a valid pulse signal from the ignition coil.
* ***Common causes of a P0350 code include:***
** Faulty or shorted primary or secondary circuits
** Defective or damaged ignition coils or coil packs
** Disconnected, frayed, or otherwise faulty wiring and connectors[br]