Need help identifying ticking sound.

Hi all, I've got an automatic 2000 SR5 TRD with 140,000 miles. And about a week ago I noticed it was making a light ticking sound that increased with the throttle. I'd notice it in the morning, after pulling out of the driveway I could hear it for the first few blocks of my commute until I got on the freeway and was going too fast to hear it. But by the time I got to work 20 mins later, when I was going slow again I couldn't hear it. And if I were to go to lunch in the middle of the day, I couldn't hear it then. So I'm wondering if it has something to do with temperature? Its been getting colder in Utah and the other day I didn't drive the truck for 2 days, and then on the 3rd day it was as cold as it has been, and the knocking seemed slightly louder. And then later in that day after the sun was out, I couldn't get the sound to replicate.

Trying to troubleshoot and narrow it down. It only happens when accelerating. On that coldest day, I did hear it when it was idling, but I haven't been able to replicate that since. It doesn't make the sound when in neutral either, even if I apply some throttle.

I should add that I'm not the best mechanically but I'm slowly trying to amend that. Trying to keep this truck on the road for another decade so I'm trying to learn and work on things myself, but I'm not sure where to start with this or even if its an issue at all? I've checked the oil and it is within the ok range.

Thanks for any insight.

 

It sounds like an exhaust leak, a leak at the manifold is commonly described the same way you're describing what you're experiencing. On those cold mornings might be able to pop hood and see the exhaust leak, at least until it warms up under there. But the idea is the slight opening or crack in exhaust piping is larger after metal cools down and retracts. As it runs and gets hot the crack seals itself up and usually doesn't reappear until it cools off enough. Sounds like a possibility in your scenario

 

Sweet, thanks. Is there a way to try to confirm this or test it further to rule out anything else?
Thanks again

 

Kinda just what I mentioned about seeing the leak, you know like the way hot looks when it's cold out. You shouldn't see any of that anywhere except for the end of tail pipe. Put a rag or something partially in the exhaust tip(temporarily) to help force that leak to expose itself, if there is one. That testing make sense? By sound you describe I'd think you'd see it at the exhaust manifold under the hood.
When was last oil change? You due for an oil change? You can get some tapping or ticking sounds when you get some heavy miles on the engine oil. I've noticed this myself