Impreza RS Coupe AWD F4-2.5L SOHC (1999)
Spark Plug: Specifications
Item
Designation
Spark plug
Type and manufacturer Standard
RC10YC4 .......... CHAMPION
Alternate BKR5E-11 .......... NGK
Thread size mm
14, P = 1.25
Spark gap mm (in)
1.0 - 1.1 (0.039 - 0.043)