Spark Plugs - Revised Recommendations
Number 87-6(Gasoline)-14 Date 12/86Subject: REVISED SPARK PLUG RECOMMENDATION FOR PREVENTION OF PLUG FOULING
1987 PASSENGER CARS EQUIPPED WITH LB4 4.3L V-6 (VIN CODE Z) AND LG4 5.0L V-8 (VIN CODE H) ENGINES
Incidents of spark plug fouling on early 1987 passenger vehicles equipped with 90 degree V6 and V8 engines and R43TS spark plugs can be corrected by the installation of a higher heat range spark plug. The new plug is a type R45TS equipped with a copper core, P/N 5613957.
A copper core spark plug can be identified by a "dot" after the "AC" logo on the porcelain portion of the plug. (Example: AC.R45TS) Every effort should be made to insure that the plugs to be installed are copper core type.
The following carline/engine combinations are affected:
Carline Engine
Grand Prix LB4 (VIN Code Z) 4.3L EFI
LG4 (VIN Code H) 5.0L Carb.
Firebird LG4 (VIN Code H) 5.0L Carb.