ENGINE NOISE/ROUGH IDLE REDUCED POWER

1987-89 S/T TRUCK, M VAN WITH 2.5L (VIN CODE E) ENGINE

THIS BULLETIN CANCELS AND SUPERSEDES BULLETIN 89-161-6A, DATED MAY 1989. ADDITIONAL SERVICE PROCEDURES HAVE BEEN INCLUDED. ALL COPIES OF 89-161-6A SHOULD BE DISCARDED.

Comments regarding rough idle/engine noise/low power following removal of the intake manifold on 2.5L (VIN Code E) engines have been traced to the intake manifold bolt spacer not being reinstalled (see illustration on reverse side for location). The spacer prevents interference between the intake manifold bolt and the #4 cylinder intake pushrod.

If this condition is encountered, reinstalling the intake manifold bolt spacer in the correct location and replacing the #4 cylinder intake pushrod will restore engine performance.

If the spacer is missing, a spacer can be made by using two flat washers, P/N 331247 (3/ 8" I.D. x 3/4" O.D. x 1/8"). Place both washers on the bolt, install bolt and torque to 28- 40 Nm (22-30 lbs/ft).

Parts are currently available from GMSPO.

When making these repairs within the provisions of the vehicle warranty, use:

Labor Operation Number: T7975 "Reinstall intake Manifold Spacer, and Replace #4 intake Push Rod"

Labor Time: M Van - 1.2 Hrs Sr/ - .9 Hr

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.