SERVICE GUILD: ENGINE MISS/ BACKFIRE/HES. POOR ENG. GROUND

MODELS AFFECTED: 1987 SKYHAWKS WITH THE LL8 2.OL L-4 ENGINE (VIN CODE 1)

If a customer comment is received concerning a miss, backfire, or hesitation, perform the following electrical ground check first. Trace back from the battery negative cable to the transaxle. The transaxle electrical ground should be secure. Torque the cable/strap to 10-14 N.m (or 7.5-10.0 ft. lb.).

A loose ground at this point can cause the direct ignition system (DIS) module to misinterpret the crank sensor signal. The DIS could become temporarily out of sync, and this could lead to an engine miss/backfire/hesitation problem.

This bulletin is for information only.

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.