Is this engine coolant on my spark plugs? P0300

JARblue

Interesting idle symptoms. Because my Z does some weird idle stuff too. It has been doing it for years and never thrown a code. Literally since 20K miles when the car was completely stock. After 100K miles I've done various mods, tune, relearn procedures, etc and it still does it. Shifting while driving is normal.

It will often rev up multiple times before settling down at the 750-800 range. My experience is it is worst when the car is hot and then sits for an hour or more. It will rev up to around 1200 and hold for 3-4 sec, then drop to 800 for a short sec, then rev up to 1600 for 2-3 sec, then drop to 800 for a short sec, then rev up to 2000 for a sec and then slowly increase to 2500+ before dropping to 800 and a normal idle after.

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