Engine - Poor Performance/Noise/Misfire/Rough Idle
Bulletin 87-6-9Date
Mar. '87
Ref. No. 87-091-6
Corp. Ref. No. 736101
SUBJECT: POOR OR NOISY ENGINE PERFORMANCE
MODELS AFFECTED: 1987 CENTURYS WITH THE LB6 2.8L MPFI V6 ENGINE (VIN CODE W)
Some 1987 early production Centurys with 2.8L multi-port fuel injection engines manufactured prior to September 8, 1986, may exhibit unsatisfactory engine performance due to valve train malfunction. Poor engine performance may be described by the customer as an engine noise, misfire, or rough idle. Poor surface finish on the valve or guide resulting in valve-to-guide wear or seizure, has been found on some early production engines.
If customer comments are received concerning any of the above conditions, inspection of the valve train should be performed for broken, bent, or stuck valves and transfer and/or smearing of metal on the valve stems. If any of the above conditions are detected, BOTH ALUMINUM CYLINDER HEAD ASSEMBLIES MUST BE REPLACED.
Additionally, the top surface of each piston should be inspected for any evidence of contact with stuck valves. Replacement of the complete engine assembly is required if valve contact is evident.
Use applicable labor operation.