Idle Question

I noticed over the last few weeks that when stopped in gear, I feel a light, intermittent vibration. Didn't think much of it until today, when noticed that this vibration occurs when the idle speed drops, as indicated by the tach. It's not related to the A/C compressor cycling. It seems to go through a cycle where it drops below 500rpm for a few seconds, then back up to normal. It vibrates the cab when it drops below 500rpm.

It's the 2.7L automatic. I assume this is not normal? Truck doesn't even have 5K miles on it yet.

 

https://www.tacomaworld.com/threads/truck-idles-rough.533971/#post-17148275

Jump on the band wagon

 

Totally normal. If you were to keep heat/ac off the compressor would not be needed and the truck wouldn't have to ramp up RPM's to generate more power. This is a fuel saving measure and it actually works very well. The truck barely sips on gas in traffic jams/at idol, but it is pretty unpleasant.

 

My truck does the same thing. Thought it was strange too. 14 k and it hasn't changed