Not the usual engine noise or tick

Hi everyone, new member but long time thread reader and fan.

The last 3 days I’ve scoured the internet reading every thread across multiple sites on anything related to engine noises and ticks and the causes and solutions. Of all the threads I’ve read and videos I’ve watched and listened to, I’ve not found anything similar to what is going on with my 95 3.4 taco, so here I am looking for any help or advice I can get. As soon as I learn how I’ll upload a video, thanks in advance.

truck has 229k, automatic trans, noise started about 6 months ago. It’s a very irregular clicking, ticking sound that is very audible. The noise only starts after the engine is warmed up and goes away under load ( no ticking whatsoever upon start up or while engine is cool). Once warmed up If I put it in gear, or rev the engine the noise stops. No sound while driving until I get to my destination and put it in neutral or park. If I leave the truck idling long enough it will quiet down and eventually stop. The ticking does not coincide with the rpm’s, it’s spurratic and sounds like it’s coming from the lower bell housing. Thought it could possibly be rod bearings but not sure

I’ve changed out all spark plugs and coils
Changed oil
Ran sea foam in fuel
Replaced hoses from evap canister

only new thing I learned about the ticking noise is that it would be louder and more consistent during the hot summer months than it is now heading into winter with cooler weather.
The other thing I learned last night is sitting in park after driving and it’s actively making the noise, turning the ac ON will make the noise stop immediately and turning the ac OFF it returns

 

On the drivers side fender well is the carbon canister, that box will make funny noises that are temperature related. Try taking the fuel cap off and see if it goes away.

 

Is the ticking more prevalent near the front of the engine or near the back, or more on the passenger side or the driver's side?

Could be that your AC Idler pulley bearing is on the way out. That's the pulley that you access by removing the rock guard and looking at the passenger side behind the radiator. If that's the case, it will get noisier and the noise will become more consistent noisier as time goes by.

Could also be something to do with the AC compressor itself. You wrote that the noise is louder during the hot summer months, and that's when you are most likely to use the AC. You could loosen the belt to the AC so that the AC won't turn when the engine is idling and see if the noise goes away. You can do that by loosening and moving the AC Idler pulley assembly away from the belt.

You could also buy a stethoscope at one of the car parts stores and use it to locate/isolate the ticking noise.

You could also turn the radio all the way up when you drive so that you don't hear the noise

 

Took it for a drive to get it warmed up good enough to make the noise again, tried the gas cap as you recommended and it didn’t change, I think it might have been just a coincidence with the ac the other day

After messing with the truck some more today and doing a little more digging, I think I’m convinced it’s the flex plate making the noise
Makes the noise in gear at an idle until I give it a little gas

I took a video but I can’t get it to upload

 

I really appreciate the input and help

 

Thank you for your interest in helping

 

See if you can move the crankshft back and forth with the motor stopped. I have seen in extreme cases a crank wiggle back and forth enough to make a noise.