Engine Control - Idle Surge/Hesitation

91chevy24

GMC TRUCK
DCS MESSAGE ID: 4858
BULLETIN NUMBER 166003


SENT 04/05/91 5:00 PM


SUBJECT: IDLE SURGE/HESITATION DURING COLD START
MODELS: 1991 "T1" GMC SYCLONE

Some customers may comment about an idle surge or hesitation condition during a "cold " engine start.

To correct this condition a new PROM has been released.

VEHICLES INVOLVED

All 1991 Syclones built after VIN M8801522 were built with the new PROM.

Some Syclones built prior to the above VIN breakpoints will also have the new PROM. These trucks will have the following information handwritten on the white ECM bar code label.

PROM P/N 16163961 - Broadcast AYBM Updated (date).

If the vehicle is built before the above VIN breakpoint and DOES NOT have the update note written on the bar code label the new PROM may correct the idle surge/hesitation condition.

SERVICE PARTS INFORMATION

Part Number 16163961 - PROM

To obtain the above PROM contact the GMC Truck Technical Assistance Center (1-800-624-2022) and one will be provided.

WARRANTY INFORMATION

For vehicles repaired under warranty use:

Labor Operation: T0500
Labor Time: 0.8 hr.

NOTE: Labor Operation is coded to base vehicle coverage in the warranty system.