P0304 2016 Toyota RAV4 Code - Cylinder 4 Misfire Detected

P0304 indicates that the engine control module (ECM) has detected a misfire in cylinder 4.

Common symptoms include rough idling, poor acceleration, reduced fuel efficiency, a flashing or steady check engine light, and possible engine hesitation.

Potential causes include a faulty spark plug, a bad ignition coil, a clogged fuel injector, low cylinder compression, or a vacuum leak near cylinder 4.

It’s not recommended. Driving with this code can cause further engine damage, lead to increased emissions, and potentially harm the catalytic converter.

Start by inspecting and replacing the cylinder 4 spark plug or ignition coil if necessary. Clean or replace the fuel injector, and check for vacuum leaks or low compression.

Costs vary depending on the issue. Replacing a spark plug or ignition coil may cost $100-$300, while diagnosing and fixing more complex problems like low compression could be more expensive.

While unlikely, a severely clogged air filter can affect overall engine performance, which may contribute to a misfire if other issues are present.

If swapping the ignition coil from cylinder 4 to another cylinder moves the misfire code to the new cylinder, the ignition coil is likely faulty.

If the misfire is caused by a partially clogged injector, a high-quality fuel system cleaner may help resolve the issue.

Not necessarily. It could be a simple issue like a worn spark plug, but ignoring it can lead to more serious engine damage over time. Prompt diagnosis is key.