## PGM-FI System

#### DTC Troubleshooting (cont'd)

11-263

Any combination of the

DTC 71: | No. 1 Cylinder Misfire
DTC 72: | No. 2 Cylinder Misfire
DTC 73: | No. 3 Cylinder Misfire
DTC 74: | No. 4 Cylinder Misfire

NOTE: If the misfiring is frequent enough to damage the catalyst, the MIL will blink whenever the misfiring occurs. When the misfiring stops, the MIL will remain on.

1. Troubleshoot the following DTCs first if any of them were stored along with the random misfire DTC(s) :

DTC 1: Primary Heated Oxygen Sensor

DTC 3: Manifold Absolute Pressure sensor

DTC 4: Crankshaft Position Sensor

DTC 12: EGR system

DTC 14: IAC Valve

DTC 21: VTEC System

DTC 45: Fuel System

2. Test-drive the vehicle to verify the symptom.
3. Find the symptom in the chart below, and do the related procedure in the order listed until you find the cause.

   Symptom | Procedure(s) | Also check for:
   Random misfire only at low engine speed and under load | Test the fuel pressure (see page 11-131). |
   - Low compression
   - Contaminated fuel
   Random misfire only during acceleration | Test the fuel pressure (see page 11-131). | Malfunction in the VTEC system (see page 6-9)
   Random misfire at high engine speed and load, or under random conditions | Test the fuel pressure (see page 11-131). | Correct valve clearance (see page 6-14)