How To Fix P0304 On A 98 Nissan Altima

P0304 code definition

P0304 is a diagnostic trouble code seen when a misfire is detected in cylinder 4. This code may exist seen with other misfire codes and lean / rich codes.

What the P0304 code means

The P0304 code will be seen in cars where the ECU has detected that cylinder 4 is not firing properly. The ECU monitors the operation of all cylinders to ensure they are all firing on time, then when one misfires repeatedly, a Bank check Engine Lite is set.

What causes the P0304 lawmaking?

Faulty spark plug
Faulty plug wires, cap and rotor, and/or scroll pack
Mechanical engine issue
Intake leak
Fuel problems

What are the symptoms of the P0304 code?

Engine running poorly or having problem staying running
Check Engine Lite present
Misfires
Lack of engine power
Decreased fuel mileage

How does a mechanic diagnose the P0304 code?

The mechanic will begin by hooking up a scan tool to the DLC port to determine which codes are present.
Freeze frame information will be associated with every code institute and should be noted for use on the test drive.
The codes will now exist cleared and a road test performed under like conditions to the freeze frame data from before.
Next, a visual inspection will exist performed looking for damaged wires, worn or broken components, or visible leaks.
Next, the scan tool will be used to monitor the misfire counter for cylinder 4.
Then, the browse tool will be used to look at the long-term fuel trims to meet if fuel issues are nowadays and the intake air pressure checked to see if vacuum leaks are present.

Common mistakes when diagnosing the P0304 code

Mistakes can be made when components are non tested or when unnecessary components are replaced. To avoid this, follow all steps without skipping whatever. Replacing the spark plugs and wires fixes this issue for most vehicles. However, the entire system must be tested before determining what to repair.

How serious is the P0304 code?

P0304 should not preclude the vehicle from being driven to a prophylactic location once symptoms showtime. With the potential for drivability problems associated with this code, it is advised to have it repaired as soon as possible for safe vehicle operation.

What repairs tin can ready the P0304 code?

Spark plugs replacement
Replacement of cap & rotor, curl pack, plug wires (depending on vehicle)
Repair of engine mechanical issues
Fixing air leaks
Repair of fueling faults

Roll pack equipped vehicles with higher mileage may experience gyre pack failure. An piece of cake way to test if the coil itself is at mistake is to move the suspect coil pack to another cylinder. And then test drive the vehicle to see if the code changes to the new cylinder. If it does, then the coil pack itself has failed.

Depending on yr, vehicles will exist equipped with either curlicue packs which are the near modern, spark plug wires which are a little scrap older, or a distributor cap and rotor which is ordinarily on carbureted vehicles. All of these are considered habiliment items, and are prone to failure on higher mileage vehicles. The spark plug wires and cap and rotor are items that are by and large replaced along with spark plugs at routine intervals.

An avant-garde level scan tool volition be needed to properly diagnose P0304 - one that does not just simply read the lawmaking, but gives access to live engine information. This data will be needed to runway misfires and view both fuel and intake information.

Need help with a P0304 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and volume an appointment online or speak to a service advisor at ane-800-701-6230.

Check Engine Calorie-free

P0304

trouble codes