Engine - Loss of Power and Performance

91chevy12

Number: 91-259-6E

Section: 6E

Date: March 1991

Corp. Bulletin No.: 136504R


Subject: REDUCED PERFORMANCE AND POWER


Model and Year: 1991 U VAN WITH 3.1L ENGINE


THIS BULLETIN CANCELS AND SUPERSEDES DEALER SERVICE BULLETIN NO. 91-221-6E, DATED MARCH 1991. VIN BREAKPOINTS HAVE BEEN ADDED. ALL COPIES OF 91-221-6E SHOULD BE DISCARDED

Condition: Some owners of 1991 U-vans with 3.1L (VIN D) engine built prior to vehicle number MT1 23361 may comment about reduced performance and power.

Cause: The ECM (Electronic Control Module) may be incorrectly retarding the engine because of incorrect signal from ESC (Electronic Spark Control) module.

Correction: If normal diagnostics as described in your shop manual (Section 6E2-B-3) do not correct this condition, replace ESC module with P/N 16126761 (Broadcast Code ANRZ).

Parts are currently available from GMSPO.

Use applicable Labor Operations And Times.