3rd Gen engine noise when accelerating up hill

I can not for the life of me figure out what this noise I keep hearing is and its extremely hard to recreate. Its sounds like a brief one to two second mixture of a diesel engine and a tin can full of marbles. it only happens when I'm accelerating up hill or under load. Tacoma is a 2021 with 20k miles of it. Has anyone experienced this?

 

Engine ping? You might possibly have gotten a bad tank of gas. A quick way to rule this out is to wait until your fuel tank is nearly empty and then refill it with Premium fuel; if the noise goes away for that tank, then you're hearing detonation.

 

Yeah Ive been looking into engine ping being the issue. If the Premium resolves issue is there a way to make sure it doesn't happen with regular?

 

Ill give it a look tomorrow and see what I can find. I will be so stoked if this is the issue haha

 

Does it happen in every gear?
Can you ID if it happens as you cross a certain rpm as you accelerate?
Is it under WOT or partial throttle as well?
Can you ID if the sound is coming from the front or the rear or mid truck?
Is there any shaking to go with it?

It could be bad gas, but it could also be something lose under the truck, like loose skids, loose exhaust etc.

 

Octane knock. Detonation. Pinging. All the same thing. I’ve heard it a few times on the 3.5L while running 85 octane. This engine has knock sensors and should adjust timing if they detect knock so it shouldn’t last long in each occurrence. As stated already, if your state has 85 octane as the minimum grade fuel, try 89 or 91 and see if it goes away. If it does, talk to your dealer as your computer may not be compensating for knock. I noticed mine after getting KDMax tuned. Coincidence or not, I don’t know. But 87 octane sounds much better in my instance.

 

Check your exhaust heat shields. The exhaust will vibrate under load and may make those rattle. One of mine was bent and made a marbles sound.

 

Its usually when I'm driving slow just hitting an incline and partial throttle accelerating uphill. It has been happening for a while but Ive been hearing it more frequently lately.

I think the sound is coming from under drivers seat but its hard to pinpoint and recreate.

Not sure what gear I'm in when it happens because its in automatic and happens randomly Ill try to keep an eye on the RPMs when I notice the sound. Ill definitely do a walk around to try to identify anything loose

 

This is starting to sound more like a shield or plate or exhaust noise; pretty much anything suspended under the vehicle is suspect. How old is your Taco, how many miles on it, and what state do you live in (or does your truck visit states in the winter which use salt on the roads)?

 

Im hoping this is the case and its not more serious. Its a 2021 with 20k miles on it I first noticed the sound at around 10k but was very infrequent so didn't think anything of it. Good weather, no salt, and very easy light off roading.

 

Mine has pinged since day one on regular under load. It's the primary reason I generally use 93. Over 65K miles and still the same. Dealer gave me the ole "That's normal" spiel and I considered it my problem at that point.

89 fixes it as well. Sucks, but is what it is.

 

Yeah, it does sound like a loose item.

OP, get under the truck when it's cold and grab the exhaust system and shake it as well as the skids. It does sound like something may be loose.

At the same time, just in case you got some really bad gas, I would throw a tank full of premium in it.

 

Do you have skids? My crossover was rattling on my skid when I first installed them until I put a washer to sun the skid down a bit.

 

Section 8-1 of the (2020) owners manual:

 

They need to explain that a little better. What they should have said is, if you hear knock, fear not, your engine will eventually adjust to the shitty fuel, your gas station has, by retarding ignition and valve timing, blah, blah, blah.. But to just say what it said without an explanation is pretty bad.

 

When my 2020 was under 1k miles it did something similar going up a steeper grade at 50 mph...the chipmunks would get pissed and make more noise, but thats long gone. At almost 16k miles the truck runs unreal.

 

Same here, mine has always done this on regular gas. Dealer said it's "normal" so I tend to run premium and it goes away.

 

I would bet it is the exhaust. The one on my pro started doing it at about 29000 miles. It was internal the baffle had somehow started rattling. Pro's have stainless steel exhaust. My dealership replaced it under warranty. Was at the dealership a week ago for 90,000 service and service manager brought it up. Said it was the only time he has seen it.

 

Oh wow I cant believe this is actually in the owners manual haha

 

It kind of makes sense; the most optimal timing, from both a power and economy perspective, for the ignition spark event should bring the engine to the point of incipient detonation (i.e. light pinging). Letting owners know some light pinging can be expected might reduce the number of unnecessary service visits.