DTC P0300, P0301, P0302, P0303, P0304: Random Misfire Detected and Any Combination of the Following: (2002-2004 models); No. 1-4 Cylinder Misfire Detected (2002-2004 models)
NOTE:
- If the misfiring is frequent enough to trigger detection of increased emissions during two consecutive driving cycles, the MIL will come on, and DTC P0300 (and some combination of P0301 through P0304) will be stored.
- If the misfiring is frequent enough to damage the catalyst, the MIL will blink whenever the misfiring occurs, and DTC P0300 (and some combination of P0301 through P0304) will be stored. When the misfiring stops, the MIL will remain on.
- Troubleshoot the following DTCs first if any of them were stored along with the random misfire DTC(s):
P0107, P0108, P1128, P1129: Manifold absolute pressure (MAP) sensor
P0171, P0172: Fuel system
P0335, P0336 (P0339)*: Crankshaft position (CKP) sensor
P0505 (P0506, P0507)*: Idle control system
P1259 (P2646, P2647)*: VTEC system
P1361, P1362 (P0365, P0369)*: Camshaft position (CMP) sensor B
P1519 (P0511)*: Idle air control (IAC) valve
*: 2004 model
- Test-drive the vehicle to verify the symptom.
- Find the symptom in the chart below, and do the related procedures and checks, in the order listed, until you find the cause.SYMPTOM CHART
Symptom Procedure(s) Also check for: Random misfire only at low RPM and under load Check fuel pressure (see FUEL PRESSURE TEST ). - Low compression.
- Low quality fuel.
Random misfire only during acceleration Check fuel pressure (see FUEL PRESSURE TEST ). Malfunction in the VTEC system (see VTEC ROCKER ARM TEST ). Random misfire at high RPM, under load, or under random conditions Check fuel pressure (see FUEL PRESSURE TEST ). Correct valve clearance (see VALVE CLEARANCE ADJUSTMENT ).