IDLE SPEED UNSTABLE SURGE ON DESCENDING GRADES

VEHICLES AFFECTED: 1987 'J AND L' VEHICLES WITH 2.0L OHV-TBI (VIN CODE 1) L-4 ENGINE

Early production 'J and L' vehicles (Cavalier, Firenza, Tempest, Baretta, and Corsica) may trigger some customer comments in the following areas:

1. Surge on long descending grades with a slightly cracked throttle, and more pronounced at higher altitudes (manual and automatic transmissions).

2. Unstable idle speed on higher mileage manual transmission vehicles only where the idle RPM will oscillate up to 300 RPM over a continuous period with steady operating conditions.

The following is a list of service PROMS and their applications:

'J' Body Automatic Transmission Service PROM # 16071643 'J' Body Manual 4-Speed Trans. Service PROM # 16071647 'J' BOdy Manual 5-Speed Trans. Service PROM # 16071652 'L' Body Automatic Transmission Service PROM # 16071656 'L' Body Manual 5-Speed Trans. Service PROM@ # 16071661

Use normal Labor Time Guide for PROM replacement.

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.