2016 Tacoma engine knocking and idle issue

Hello I'm new to this forum. I'm hearing some weird loud knocking sounds coming from my tacoma engine and was hoping the experts on this forum would be able to help diagnose the issue. Also every time the knock happens, the engine rpm will go up 100-300 rpms. I've uploaded a video on YouTube, please take a look. This noise is very repeatable, only happens when the engine is at normal operating temps in both idle and drive. The AC and all accessories are off, no steering input. My truck is currently with our local Toyota Service dept for 5 days getting diagnosed but talking to the master tech they have never heard this before. Please help. Thanks.

https://youtu.be/5Jp8G3sMbDA?si=Hv3FvyqRPRRiCFsf

 

How long have you owned this Tacoma?

 

I purchased it new. It has approx 80,000 miles right now.

 

The time intervals between each knock occur very randomly, at least it seems that way to me. This has been happening for 2-3 weeks now.

 

As we all know know these engines are inherently noisy. There are quite a number of these types of vids posted on here. Yours is definitely making that sound you describe. Is your truck completely stock without any codes?

 

Yes it’s completely stock and I have done all the recommended maintenance since new with oil changes every 5k. I’ve seen many of the Tacoma engine ticking videos but never one with the loud knock like mine and don’t have the idle issue accompanying. No codes, no check engine lights. The toyota tech ran it through their diagnostics and said everything seems normal. They confirmed the knocking noise as well.

 

If yours is not Offroad or Pro trim, It could be a vacuum pump. Or , sticky hydro lash adjusters

 

It’s the SR5 model

 

The vacuum pump in on the rear of the passenger side bank (bank 1). If noise is coming from the area, most likely the pump.
If not, likely lash adjusters.
Does noise go away when increase rpms?

 

Yes knocking goes away at higher rpm’s but it could just be due to loud engine (parked or drive) or road noise drowning it out too. Sometimes when you come to a full stop it could take over 15 seconds before the knocking starts however other times you can hear it knocking (quicker intervals) towards the end of coasting when the rpm’s are very low. It’s repeatable but random, if that makes any sense.

Fwiw, I also noticed a couple times when the rpm’s jumped unusually high (about 300-400 rpm’s) the knocking would completely go away for 10-15 minutes.

I have not checked oil level since it happened and can’t because it’s still at the shop right now.

 

hope they will come up with the answer.

if they do let us know

 

I have that knock once in a while. Usually during the hot idle. Somewhere around the front of the engine driver's side. I ruled out the injectors cleaning cycle and the vaccum pump. I believe this caused by one or a few sticky lash adjusters.

 

Do you think that circumstance is the lash adjuster slamming down into the bore in the head? I have it also sometimes. It’s been more often lately, somewhat concerning.

My guess is the extra oil pressure when revving builds up and keeps them tight to the rocker, and low pressure at idle doesn’t provide enough cushion…but just a hunch.

 

Could be both. Sagging inside of the bore or the plunger movement is restricted

 

Makes sense. Hope it doesn’t end up causing problems. Seems like a lot of the engines do this.

 

Dumb question, would changing of oil brands make a difference? Still using 0w-20 but the recent oil change I switched from Mobil1 to Valvoline because they were on sale.

 

I don't think so.

 

I have a similar sounding knock from the passenger side. Some info on my truck:

• OR so no vacuum pump
• Current mileage ~40k
• Truck has been supercharged for the last ~15k miles
• It was making the noise prior to the supercharger install
• Noise is more noticeable when driving in stop and go traffic
• Blackstone oil analysis from 5k miles ago said no abnormal wear; I took another sample last night when I changed the oil so lets see what that one says.

Personally I think it might be a sticky lash adjuster like others have said. With no out of spec wear indicated from the oil analysis report I've decided to just monitor it for now. If anything changes I'll likely take off the valve covers to inspect further.

 

Got my vehicle back today. The problem is fixed but they're not sure what was causing the knocking in the first place. All they did was update the ECU for the Power steering TSB and that seemed to fix the knocking problem as well. Either way it's fixed so I'm happy. Thanks everyone for your help.

 

Could you share tsb# that they applied to your truck?