1990 Corvette: Service Manual Update: SEC. 6D4 Spark Plug Coding Chart
Estimated Reading Time: 1 MinutesSubject: SERVICE MANUAL UPDATE-SEC. 6D4 SPARK PLUG CODING CHART
Model and Year: 1990 CORVETTE
Source: Chevrolet Service Bulletin
Bulletin Number: 90-253-6D - (06/26/1990)
The Spark Plug Coding Chart shown in Figure 2, Page 6D4-3, in Section 6D4 "Ignition System" in the 1990 "Y" Carline Service Manual has been revised as shown in the attached Figure 1. Please make a note of these changes for future reference.
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