DTC P0300: Random Misfire and Any Combination of the Following; DTC P0301: No. 1 Cylinder Misfire Detected; DTC P0302: No. 2 Cylinder Misfire Detected; DTC P0303: No. 3 Cylinder Misfire Detected

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 P0303) 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 P0303) will be stored. When the misfiring stops, the MIL will remain on.
Before you troubleshoot, record all freeze data and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).

Troubleshoot the following DTCs first, if any of them were stored along with the random misfire DTC(s):
P0106, P0107, P0108, P1128, P1129: Manifold absolute pressure (MAP) sensor

P1162-P1169: Air fuel ratio (A/F) sensor (Sensor 1)^*1

P1157, P1158, P1159, P1162-P1167: Air fuel ratio (A/F) sensor (Sensor 1)^*2

P0133, P1157, P2238, P2252, P2A00: A/F sensor (Sensor 1)^*3

P0171,P0172: Fuel system

P0335, P0336 (P0335, P0339)^*3 : Crankshaft position (CKP) sensor

P0401, P1491, P1498 (P0401, P0404, P0406)^*3 : Exhaust gas recirculation (EGR) system

P0505 (P0506, P0507)^*4 : Idle control system

P1259 (P2646)^*4 (P2646, P2647)^*5 : VTEC system

P1361, P1362, P1366, P1367 (P0340, P0344, P0365, P0369)^*3 : Camshaft position A/B (CMP A/B) sensor

(Top Dead Center 1/2 (TDC 1/2) Sensor)

P1519 (P0511)^*3 : Idle air control (IAC) valve

*1: 2000-2001 M/T models

*2: 2002-2003 models

*3: 2004-2006 models

*4: 2004 model

*5: 2005-2006 models
Test-drive the vehicle to verify the symptom.
Find the symptom in the chart below, and do the related procedures to find the cause.

CYLINDER MISFIRE CHART

Symptom	Procedure(s)	Also check for:
Random misfire only at low RPM and under load	Check fuel pressure. 2000-2003 M/T models (see 2000-2003 M/T MODELS ) 2001-2003 CVT models (see 2001-2003 CVT MODELS ) 2004-2005 M/T models (see 2004-2005 M/T MODELS ) 2004-2005 CVT models (see 2004-2005 CVT MODELS ) 2006 model (see 2006 MODEL )	Low compression. Low quality fuel.
Random misfire only during acceleration	Check fuel pressure. 2000-2003 M/T models (see 2000-2003 M/T MODELS ) 2001-2003 CVT models (see 2001-2003 CVT MODELS ) 2004-2005 M/T models (see 2004-2005 M/T MODELS ) 2004-2005 CVT models (see 2004-2005 CVT MODELS ) 2006 model (see 2006 MODEL )	Malfunction in the VTEC system (see VTEC ROCKER ARM TEST ).
Random misfire at high RPM, under load, or under random conditions	Check fuel pressure. 2000-2003 M/T models (see 2000-2003 M/T MODELS ) 2001-2003 CVT models (see 2001-2003 CVT MODELS ) 2004-2005 M/T models (see 2004-2005 M/T MODELS ) 2004-2005 CVT models (see 2004-2005 CVT MODELS ) 2006 model (see 2006 MODEL )	Correct valve clearances (see VALVE CLEARANCE ADJUSTMENT ).