Slight Vibration at Idle

[geops]

I was just wondering if it's normal for the V8 to have a slight vibration every few seconds while idling in park. The RPM don't seem to fluctuate which means the engine seems to be running fine. Anyone else experience those? Are they normal?

 

[BStarr119]

Right at 750 rpm I get this vibration, but as soon as the engine warms up and drops down to 500 rpm it goes away unless I hold the engine at 750 rpm. Might be a point of resonance for this V8 but definitely not a miss fire.

 

[sluggo]

Also, a reminder that on a cold start, the engine both revs higher than normal AND the timing is artificially advanced in order to heat up the cats more quickly. If the engine is at operating temperature and the idle stumbles a bit, then there's something else going on.

 

[geops]

It's warmed up and running at around 500 rpm, and there are these vibrations every few seconds. However, the rpms do not change so I don't think it's a misfire. It's not a big vibration but I can feel it when the car is still and in park.