Help me figure out this BUZZING sound

2016 Tacoma 3.5l 75k miles on it. When I changed my plugs at 65k I got a check engine light and had this buzzing sound. After pinpointing the sound to the rear driver's side coil, I changed the plug thinking it was possibly faulty and the sound disappeared. 10k miles later the sound is back. I just swapped coils and nothing changed. Guess I will pull the plug again but just curious if anyone knows that this could be? I used a metal rod on my ear to pinpoint it and every time I do this I end up in the same spot being the rear driver's side coil where it is the loudest (the one under the foam cover).

You can hear the buzz go on and off, it does this consistently at idle. If I give it gas the sound disappears.

 

What was the CEL for? Maybe pcv valve fluttering?

 

I never had it read. I just tried replacing the other plug before and in doing so had my battery disconnected and it never came back on. I do not have any check engine light right now and have been driving a ton lately for summer road trips. Realized the sound was back yesterday when using my compressor to blow a paddle board up.

 

Looks like you're missing the bolt on the foam cover on the pcv area. Can u pull that foam and see if it's coming from underneath?

 

Ya I am not sure how that came out or maybe I forgot to put it back, most of the sound comes from that rear coil/spark plug under that foam, I am gonna go check the PCV right now and see if that is more of the sound. I do not have any oil residue around it though I just looked.

 

That's just a wild ass guess from me, but I know it's kind of in the same location. It's hard to pick up audio sounds from a video sometimes.

 

Key in ignition with door open?

 

Well using a pole the sound is much louder coming off that PCV. So maybe that’s what it is. Sometimes it won’t do it either which would make sense because the valve is like intermittently sticking. Super appreciate the advice on that. I’ll have to replace it and see what it does.

is it okay to drive it in the meantime ?

 

I'm not qualified to answer that lol. Is your engine gonna blow up? Most likely no. But you've been driving on it anyway so your *probably* good for a bit longer. Keep in mind, am an idiot on the internet.

 

It sounds like an electrical arc. Pull the coils and check for carbon tracking.

 

All my coils look really healthy. I just pulled them again this morning I can’t find any signs of anything. It’s so odd.

 

Get it scanned and see if there are any pending codes. Really look at the coil pack "stems" for micro cracks which will cause arcing, although I would think you would get the blinking CEL or a misfire code

 

I played with the PCV valve, pulled the hose off, tried to clean it a bit while leaving it installed since I am waiting for one I ordered, and since then it hasn't made the sound. So maybe something is sticking inside that. I leave for a trip tomorrow, leaving the truck at home, when I get back I will replace the valve. Thank you for the help guys, I appreciate it.

Coils looked great, plugs have 10k on them, they're the oem toyota plugs. The only thing in common each time this has occurred and started occurring was messing with the PCV valve hose in order to get the coil off. Will update in a week when I get back.

Just found this video

https://www.youtube.com/watch?v=9-BRtRYo8dg

Sounds exactly like what I have going on. Fingers crossed the $13 valve does it

 

His description is exactly what it sounded like to me. A spun bearing

 

Hey man starting to have this same noise same area before I throw time or money at it just wondering if you resolved this?

 

It was my PCV valve. I switched it out and the sound went away for awhile but now its back so I am not too sure what is going on. I might have a small leak somewhere in the line, but truck runs great with no codes and it only buzzes at idle sometimes so I just roll with it. When I initially switched it out my gas mileage did improve for a couple months, good luck!

 

Kinda sounds like mine - a faint high buzzing at idle when at stop lights.

Have no clue what it is, but it happened to me after I flushed by coolant. Engine runs great, and no leaks anywhere.

Maybe it's just another individual and harmless anomaly, because still no issues ever on my 2015 PreRunner.

 

Western Diamond back rattlesnake

 

Did you figure it out?

 

The guy you asked hasn't been here in over 2 years