For 1990-2009 cars

# REVISED IDLE SPEED CONTROL ISC HAS SILENT THROTTLE SWITCH

A revised Idle Speed Control Assembly was introduced on Dualjet carburetors for the 3.8L V-6 engine (VIN Code 9) in December of 1982. Use has been extended to Quadrajet carburetors used on the 4.1L V-6 engine (VIN Code 4), and Dualjet carburetors used on the 3.0L V-6 enaine (VIN Code E), and 3.8L V-6 engine (VIN Code A). The new ISC assembly is identified by the numeral "II" on the motor housing, as shown.

The new feature is a silent throttle contact switch that does not "Click" when actuated. When checking operation of the throttle contact switch on ISC II, follow present Service Manual procedures.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.