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P0300, P0301, P0304 OBD2 Codes in 2003 Nissan Altima 2.4L Engine - Misfire & Hissing Noise Diagnosis

Model: 2003 Nissan Altima Fault Code: P2177 Posted: 2012-12-01 19:42

My 2003 Nissan Altima 2.4L engine shows intermittent misfires with OBD2 codes ranging from P0300 to P0304. The vehicle starts smoothly when cold and warms up normally, but after about 15 minutes of idling, a noticeable miss develops. The check engine light (CEL) illuminates, and the code cycles between P0300 (random misfire), P0301, and P0304 before clearing and allowing normal operation. When accelerating, a hissing noise is heard. I have already replaced all spark plugs and checked coil packs—no issues found. The cooling fans do not activate during idle or when the engine is cold. Could this be related to a faulty thermostat or temperature sensor? Any insight into resolving this would be greatly appreciated as it's becoming increasingly frustrating to drive.

Related fault codes

P2177

Comments (4)

Anonymous 2012-12-02 13:16

The check engine light (CEL) is on—what specific OBD2 codes does your scanner show? Please stop erasing the codes. Do you have an OBD2 scanner? Plug brands vary significantly; ensure you used OEM-quality plugs like NGK or Bosch. Cooling fans only activate when the engine reaches operating temperature—verify coolant level and check if the vehicle overheats. Turning on the AC can trigger fan operation, so try this as a simple test.

Anonymous 2012-12-03 21:51

The hissing noise could indicate a significant vacuum leak. Vacuum leaks disrupt fuel/air mixture and often cause misfires. Have you checked for any fuel trim codes (e.g., P0171/P0174) in your OBD2 scan? These can provide additional clues about the root cause.

Anonymous 2012-12-10 16:18

I previously encountered a similar issue with both a 2003 and 2005 Nissan Altima 2.4L. The vehicle displayed P0301, P0302, P0303, and P0304 codes intermittently. I tested each ignition coil using an inline spark tester—initially all showed consistent sparks, but after several minutes, some began misfiring as the spark weakened, indicating failing coils. In one case with a Honda 4-cylinder, the owner replaced plugs and coils but still had a P0304 code; inspection revealed missing gasket pieces between the cylinder head and intake manifold on cylinders 3 and 4. After cleaning with carb cleaner, the engine responded well during acceleration—after replacing the gasket, the issue was fully resolved. For your cooling fan: tap it gently with a hammer—if it spins freely, the fan is likely defective.

Anonymous 2012-12-10 18:01

The hissing noise may also be caused by a clogged catalytic converter—this is relatively common in Nissan vehicles and can lead to backpressure issues and unusual noises during acceleration.