Engine Controls - Surging Or Stumbling When Cold

Classification:
EC97-042a

Reference:
NTB98-026a

Date:
April 15, 1999

SURGING OR STUMBLING WHEN COLD

This amended version of NTB98-026 corrects information in the Applied Vehicles section.

Please discard all paper copies NTB98-026.

APPLIED VEHICLES:

1994-95 Truck (D21) with V6 engine - M/T only
1994-95 Pathfinder (WD21) - M/T only

SERVICE INFORMATION

Use this bulletin to diagnose and repair an applied vehicle with a manual transmission that exhibits engine surging or stumbling, and black smoke from the exhaust when the engine is started after a cold soak (32°F and below). The incident may last a few minutes before the engine begins to warm up.

A countermeasure ECM is available to resolve this incident. Use this ECM as a repair for this incident only. For all other repairs in which the ECM is replaced, use the normal service part number.

SERVICE PROCEDURE

1. Use the flowchart to confirm that ignition timing and base idle speed adjustment are within specification.

2. Make adjustments as necessary.

3. Allow the vehicle to cool to the temperature when the incident occurred and retest the vehicle to see if the incident is still present.





4. If you confirm ignition timing and base idle are within specification and the incident is still present, replace the ECM with the countermeasure ECM (see Figure 1 for location of ECM).





PARTS INFORMATION





CLAIMS INFORMATION