Engine Controls - Idle Speed Rise When Clutch Depressed

90chevy27
Number: 90-320-6E

Section: 6E

Date: August 1990

Corp. Bulletin No.: 036512
Subject: IDLE RISE BETWEEN SHIFTS


Model and Year: 1989-90 C/K TRUCKS WITH MANUAL TRANSMISSION AND 4.3L (VIN CODE Z) ENGINE






TO: ALL CHEVROLET DEALERS

CONDITION: Some owners of the above trucks equipped with manual transmissions may comment about a slight rise in engine idle speed when depressing the clutch to shift gears.

CORRECTION: To correct this condition a new service calibration PROM should be installed. The new calibration increases the rate at which Idle Air Control (IAC) counts are removed following a rapid closing of the throttle. Use the following VIN breakpoint and application charts to select the proper PROM usage.

VIN BREAKPOINTS: 1990 Model Year

L1126446 OSHAWA (Plant Code 1)

LZ152371 FORT WAYNE (Plant Code Z)

LE144515 PONTIAC EAST (Plant Code E)

APPLICATIONS: ALL 1989 AND 1990 BUILT PRIOR TO 1990 VIN BREAKPOINTS
These PROMs will only function in service ECM (Electronic Control Module), P/N 16144288.

Parts are currently available from GMSPO.

Labor Operation Number: T0500

Labor Time: .6 Hrs