It just started. When stopped in P the knocking noise is not there. When I go into D the knocking noise is there at idle. When I accelerate and drive the knocking noise is not there and engine sounds normal.

So the knocking noise is only when stopped and idling in D.

Im thinking maybe water pump? Worn engine mount? Hope its not more serious like piston slap, bad con rod, or crank bearing. Car has 190K miles.

Any ideas???

 

We need a better idea of where the noise is coming from. Front of the motor? Back toward the transmission? Have someone hold it in D and you hunt for the noise.

 

Seems like its coming from the passenger side in the engine bay

 

Might sound weird but the motor mount bolt could have come out. You need to do a good visual inspection of that whole area.

 

Is it in the passenger side, towards the back of the engine? You might be hearing noises related to the high pressure fuel system for the direct injection system.

 

You would thing bearing or piston slap would get faster and louder when driving.

When end you bring the rpm’s up does the noise go faster ?

 

Motor mount:

Thats what I was thinking

 

When rpm goes up noise goes away. Under normal driving noise goes away.

 

I know exactly what this is, if it comes and goes on and off, after a few minutes, it’s our cars going into self cleaning mode. My car does it to. I have an is350 2018 fsport. Basically our cars have direct injectors and port injectors. And when the car sits for a minute or two they take that time to perform self cleaning by pressuring the engine by putting fuel to both the port and direct injectors. This causes the engine to sound off.

 

A long wooden dowel placed on the suspect noise while the other end is softly in your ear can point you in the right direction. A long screwdriver or stethoscope are good options too.

Heads inside and outside along the valve cover and exhaust ports.
Injectors.
HP Fuel Pump
Motor Mounts
Water Pump
AC compressor
Alternator and Idler pulleys

Have someone hold the foot brake and repeat the mount listening while in drive.

 

Interesting. But how can the injectors clean themselves unless they are fully open?

Ie. wot

 

The 2GR-FSE does not have the auto-clean feature, the FKS in your 18 does (which started being used for the 2018 MY). Of course the dedicated autocleaner does a much better job than what the FSE does without it, but even still, there really are little to no reports on carbon buildup, it really only applies to the 4GR used in the 250.

.. Back to the topic at hand, without a video, I'd just assume its the DI making that noise.

 

I may be wrong but the 2gr fse and fks may have the cleaning mode unless for the Lexus they did not implement it till 2016 here is a clip on the self cleaning mode I found for the engine
maybe Tacoma is different also for the years it operates my assumption would be the engines all have 12 injectors and they do flip flop back and forth on which are on and which are off is why also the engine makes different tunes and tones when in high pressure mode Here is the article pasted in ***Drivers may hear the self-cleaning taking place during a hot idle, and the process could last from 10 seconds to as long as 10 minutes, depending on driving patterns and the amount of build-up on the injectors.

“When you go into a hot-idle situation, the system is going to look at the time that it ran, the number of cycles the injectors went through, the temperature of the injectors and then it goes into a self-cleaning mode,” Sweers says. “Because we have the port injection, I can continue idling the engine without having any side effects.”

He compares the technology to a self-cleaning oven, as no additives are necessary.

“You stop at a light (and) it may clean for 10 seconds, you’re going to take off and stop at another light and it’s going to clean for (another) 10 seconds,” he says, noting the engine will deliver torque when a driver wants it and shut off the cleaning mode.

The 10-minute cleaning cycle occurs during longer idling, such as in a drive-thru line.

The next-generation D-4S is paired with the next generation of Toyota’s 2GR engine family, the 3.5L 2GR-FKS. The previous iteration of 2GR, 2GR-FSE, is a 4-time Ward’s 10 Best Engines winner.

Both 2GR-FKS and 2GR-FSE are all-aluminum Atkinson-cycle engines. But differentiating the new 2GR from the existing 2GR are reduced-friction oil sumps, a new variable-valve timing system that shifts between Otto and Atkinson cycles and an exhaust manifold integrated into the cylinder head, a design that has a variety of benefits, including weight reduction and the ability to use engine coolant to cool exhaust gas

 

That's excellent, really. But I'd be concerned about carbon deposits on different areas of the engine from idling.

you are saying that port injection is good for idling? I thought DI was better for idling.

 

@Ken167 Did you ever find out what this noise was? I have joined this forum only to ask your this as after hours of internet searching your description is exactly what I have. I’ve heard it’s motor mounts or piston slap or ‘they just make that noise’ but nothing about what it actually is?? Mine is a 2008 Toyota Estima with the 2GR-FE. It does the exact same thing! Warm in D makes a knocking noise. Goes away by 900rpm and no other noises while driving. Throw it in P or N at idle nothing. Only had the car for about 3 weeks and this knocking sound is driving absolutely nuts!!
Let me know if you ever resolved it.
Cheers,
Jess