Slight rumble / “rough” idle in P or N?

my 2018 2.7 auto 4x4 has had a slight little rumble in park or neutral. It stops as soon as it’s in drive or reverse. I notice it when the car is both cold or warm. Almost like a rough idle. Not rough enough to be really concerning but just enough to feel it. Seems like it’s every 5 seconds or so.
It’s been doing this since day one, and figured it might stop after break in or figured I’d ignore it eventually. Now it’s 9k miles later and it still bothers me lol

Has anyone else noticed this? Is this concerning? Normal? If you did notice, what did you do to stop the problem?

 

My RPMs surge when I have the A/C on...could that be it? Seems like its every 5-10 seconds

 

Clean the MAF sensor...

 

No AC. Just normal running condition, all air turned off

 

you think that could be it? On a brand new truck with only 9k? It was already doing that with 6 miles on it when I got it from factory. I’ll give it a shot

 

For me it was a combination of injector cleaning cycles and the AC compressor kicking on. It's normal. Note that even in cold weather the AC will still cycle to clear moisture from the system.

 

So you had those small little rumbles too huh? I guess I’m just a picky sob loll. Even the slightest abnormalities bother me

 

What vehicle are you coming from? I think this problem exists throughout all the tacos I’ve driven, both first and second gen.

 

Currently a 2018. Before was a Scion TC lol
I had a 01 Sr5 back in the day and I don’t remember it doing that but that was a long time ago

 

Yeah I imagine the Scion was smoother at idle. I’m pretty sure what you’re describing is normal and you’re just noticing the difference.

Probably a mix of this ^ and the Atkinson cycle doing its thing.

 

What is the Atkinson cycle? I tried looking it up but it didn’t say anything about the 2.7 liter 2tr-fe


Also as comfort measure to anyone else experiencing this- I ran by the dealership (a different one than the first) and they were super helpful. The first dealer at my first oil change (I do 5k intervals) totally shrugged me off and just said “I wouldn’t worry about it, you have a warranty so if anything happens you’re covered” and refused to check out my “rough idle”. That frustrates me because I don’t want to wait for something to break and leave me stranded, I like to get things handled preventatively.

Today at my 10k oil change at a different dealer, they were very helpful. They told me again it was nothing to worry about, but that they would fully inspect it with a Toyota master tech.

They put my truck on the computer and ran it for any codes (which I knew there would be none), then monitored my idle on the computer for 5 minutes in park and said there was absolutely nothing abnormal, and also were kind enough to send me off with the printed results.

Shouts out to Joe at Walnut Creek CA Toyota. Helpful service advisor! Most others don’t go out of their way to help you like he did.

 

Whoops. The Atkinson cycle is for the 6cyl, not the 4cyl. My bad, I read it in a hurry during my work break. But really, 99.999% your truck is fine.

 

my 17 does the same, my wifes old rav 4 did the same for 160 k miles of no problems this guys explains inline 4 nicelyhttps://www.youtube.com/watch?v=9skOWu-wdC8&t=190s not a big problem just nature of the beast.

 

I thought I had an exhaust leak haha. I even called the dealer.