My 300E used to idle around 500-550 smoothly. My V8 M116 idles about 50 rpm less than your picture in Drive, but around 950 in Park.

Idle speed on the gas engines is highly influenced by the amount of air making it into the manifold while idling....I dropped the in-Park RPM's on mine by almost 400 by just replacing all the rubber hoses!

Yours looks to be running normal/just fine. Does it idle smoothly?

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