P0301-CYLINDER 1 MISFIRE

For a complete wiring diagram Refer to Section 8W.

When Monitored:
Any time the engine is running and the adaptive numerator has been successfully updated.
Set Condition:
If the PCM detects that the variation in crankshaft speed between each cylinder exceeds a calibrated value, based on engine rpm and load, a fault is set.

Possible Causes

INTERMITTENT DTC

FUEL DELIVERY SYSTEM

ECT SENSOR, WIRING, OR CONNECTORS

MAP SENSOR, WIRING, OR CONNECTORS

O2 SENSOR, WIRING, OR CONNECTORS

ENGINE MECHANICAL SYSTEM

POWERTRAIN CONTROL MODULE (PCM)

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

Diagnostic Test

1.DTC IS ACTIVE

WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.

NOTE: Attempt to operate the vehicle under conditions similar to which the DTC was set.

NOTE: It may be necessary to test drive the vehicle within the DTC monitoring conditions in order for this DTC to set.

Is the status Active for this DTC?

Yes

Go to 2

Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)

2.DIAGNOSTIC INSPECTION

NOTE: Anything that affects the speed of the crankshaft can cause this DTC to set.

NOTE: When a misfire is detected, the PCM will shut down the injector control circuit for the misfiring cylinder.

NOTE: Misfire may occur and may not be caused by component failure. Any of the following conditions can cause a misfire: