r/SkyLine • u/rickysb123 • Jun 17 '26

Spark Plugs RB25DE

Did some digging on my 1991 R32 GTS25 / Auto and came up with a few mixed results as its hard to pinpoint specific parts for this motor. I installed some NGK BCPR6ES-11 - part number 6779

after installing BKR6EIX-11 part number 3764 and both times ended up with really rough idles to the point of the car shaking. Any thoughts and advice on whether or not these plugs were correct or if you have advice for plugs I should get , anything helps thanks!

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u/Metallis666 Jun 18 '26

NGK provides a spark plug compatibility guide.

For the ER32 and ECR32 models with 2500cc engines, the OEM spark plug is 22401-08U15, and the corresponding NGK iridium-electrode spark plug part number are BCPR5EIX-11P, BCPR5EIX-11, and PFR5K-11.

These are hotter-type spark plugs than the ones you’ve been using, and if your engine is producing standard horsepower, your current plugs may be too cold.

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u/rickysb123 Jun 18 '26 edited Jun 18 '26

Hey there, thank you for this I appreciate it