Strange sound

Sorry if this has already been covered. I have a 2013 Tacoma DCLB 10,000 miles, I have noticed on a few of the cold days that I have a noise that I've not heard before. The noise sounds like a valve in a way of the " Tap Tap Tap Tap" noise but this Tap noise is a little more deeper then your normal valve sound. It seems that if you pull out it increase the speed of the sound with same speed as motor, but when you come to complete stop it still tap tap tap tap pull back out and starts increasing speed with engine, and kinda seems to hear from rear of truck as well as middle and in the front, so I'm at a loss of what it is. As you know the dealer couldn't get it to make the same sound. I have heard it 2 or 3 different times. If any one has had this happen or anything like this any info would be great. Thanks.

 

You are driving a sewing machine, you'll get used to it.

 

It's cold it doesn't want to run any more than the rest of us