What does P0304 code mean?

Diagnostic trouble code (DTC) P0304 stands for “Cylinder 4 Misfire Detected.” The code indicates that the powertrain control module (PCM) has counted enough misfire events on cylinder 4 to store the misfire code for that cylinder.

How do I fix error code P0304?

Can you drive with a P0304 code?

Driving with a misfiring cylinder is potentially dangerous. If you lose power while driving or a second or third cylinder goes out, this can cause you to get into a car accident, possibly injuring you and others around you.

How much is it to fix a cylinder 4 misfire?

Depending on the exact cause, it could be anywhere from $20 to $700 or more to fix a cylinder 4 misfire. Below, we'll discuss all the possible causes of a cylinder 4 misfire. Then, we'll highlight the average price to resolve each of these problems.

Will a tune up fix a misfire?

A “tune-up” may help to resolve a misfire. A tune-up involves changing the spark plugs, ignition wires, distributor cap, and the rotor. It is a good place to start because it will eliminate some of the potential causes of a misfire if it does not already fix the issue completely.

P0304 Explained - Cylinder 4 Misfire (Simple Fix)

Do misfires go away?

However, most misfires dissipate, and your engine regains its normal speed after a second or two. But even a single misfire is usually a sign that something else is wrong and that more misfires will likely occur in the future.

Can bad gas cause a misfire?

A tank of “bad gas” (incorrect octane or old gasoline) can cause a misfire. Weak or dirty fuel injectors can restrict the flow of fuel into the cylinder leading to the wrong air/fuel ratio.

What does an engine misfire feel like?

Misfires can happen when a vehicle is under load while accelerating. This causes slow or sluggish acceleration and your vehicle may have trouble getting up to speed. You might feel a jerking motion when pressing down on the throttle. The most common cause of an engine misfire when accelerating is worn-out spark plugs.

How do I know if I have spark plug or coil pack?

Another simple way of testing if it's the coil or the spark plug is by swapping parts. Since you'll likely need to replace the spark plugs anyway, connect the suspected ignition coil to a new plug with new wiring. If it still doesn't fire, it's the coil.

What causes cylinder to misfire?

The most common causes of misfires are worn, improperly installed, and mishandled spark plugs, malfunctioning ignition coils, carbon tracking, faulty spark plug wires and vacuum leaks.

Will changing spark plugs fix a misfire?

If your engine is misfiring, you may be able to fix the problem easily by replacing your spark plugs. Spark plugs are relatively easy to remove from engines and inspect for damage, and at less than $25 a piece, they are relatively cheap to replace, too.

Can low oil cause misfire?

Low engine oil can cause a misfire, and it is very likely that the cause of the misfire was indeed the low oil pressure in your vehicle. There are three common ways low oil can cause a misfire: Your oil filter is damaged, reducing oil flow, causing improper valve timing, and resulting in a misfire.

Can a bad o2 sensor cause a misfire?

If an oxygen sensor or mass airflow sensor is failing, it could give incorrect data to your engine's computer, causing the misfire. When a vacuum line is broken, it can cause a fuel-injected motor to misfire.

Will seafoam help misfire?

Cool. I was having multiple misfires in cylinder 2, almost all at idle, and a somewhat rough idle. Plugs are new and car passed a pressure test.

What are the signs of a bad fuel injector?

What are the signs of bad gas in a car?

Why is my car misfiring after changing spark plugs and coils?

If your car misfires after you changed the spark plugs and coils, it's likely due to another problem. Other possible causes include a clogged fuel injector, low compression, or a problem with the computer that controls the ignition system. If you're not sure what's causing the problem, have your mechanic check it out.

How long can I drive with engine misfire?

In theory, you could drive thousands of miles with a cylinder that misfires. The other cylinders in the engine will continue to operate, so even though you may shake and stall along the wall (and not get much in the way of speed or acceleration), the car will still run.

Can a misfire damage a catalytic converter?

Engine misfires that are not repaired in a timely manner are the number one reason for damaged catalytic converters. The damaging conditions created by a misfiring cylinder of the engine can reduce the useful life of the vehicle's catalytic converter by years or, even worse, meltdown the converter.

What sensor is used to detect engine misfire?

The OBD II system detects misfires on most vehicles by monitoring variations in the speed of the crankshaft through the crankshaft position sensor. A single misfire will cause a subtle change in the speed of the crank.

Can a clogged fuel filter cause a misfire on one cylinder?

Random Misfire or Rough Idle

A clogged fuel filter causes low fuel pressure that results in a lean fuel condition and engine misfire. This can result in poor fuel mileage, rough idling and possibly cause the check engine light to come on. Once that light is on, it's time for a trip to the repair shop.

Can fuel pump cause misfire?

A weak pump that isn't delivering adequate pressure can cause an engine to run lean, misfire and hesitate when accelerating. The volume of fuel is just as important as pressure. A good fuel pump is usually capable of pumping at least 750 ml (3/4 quart) of fuel in 30 seconds. If it can't, there's a problem.

Can you replace only one coil pack?

You can replace one coil at a time or all at the same time. I would however recommend having all spark plugs replaced with the coils so you do not have to remove coils twice.