Truck Idles Rough

I have a 2016 SR 2.7 4 cyl, AT. About a month ago started to notice that the truck idled alittle rough at a stop while in drive at 24,000 miles. Several weeks later it's certainly rougher, and it's very noticeable when I rest it against the headrest. The door panels shake, and I also feel it gently in the wheel. Brought it to Toyota and the service reps said sapmething along the lines of 'I'm sure it's fine, trucks just run rough but we'll take a good look at it'. He talked about doing a fuel injector cleaner, but I was wondering what else might be going on. Could spark plugs be effecting this? I did hear from them today that no codes were fired off when they plugged it in, but they'll take a better look in the morning. Thanks for any input

 

Sounds like classic symptoms of a failing Crankshaft Position Sensor (CKP).

Many owners, myself included were not on the official recall nor had codes thrown but the inability to consistently get a read on engine speed due to friction or static between the sensor and the crankshaft rotor can cause all kinds of problems, rough idle was the dead giveaway that led me to the swap and it solved the issue instantly for $100 out of pocket and 20 minutes of my time

 

Yeah I thought that at first too, but he's in a 4 banger. Don't hear too many complaints about that engine..

 

So this wasn't covered under warrenty? Or did you just not want to deal with the dealership? I appreciate you bringing that up because I would not have though of that.

 

My truck had been to the dealership several times, including a field service tech ride along. The truck was running rough overall but the rough idle was intermittent and when it did get especially rough they acted like it was no big deal "they all do that" "it's a truck" and so when I learned of the CKP problems it was worth $100 out of pocket (which I could return if it wasn't the issue) to see if it resolved the issue. It did. From what I've seen aside from being on the official recall list, you basically had to be burning up your catalytic converters before Toyota would replace it under warranty. Could I have raised hell at the dealership and finally gotten them to cover it? Probably, but for a relatively cheap part I was glad to not have to deal with them....

 

Ah - I missed that one, and you're right. I think I've maybe seen one or 2 out of all of these that had a similar issue in a 4-banger. Could be something entirely unrelated OP as the CKP issues were mainly on the 2gr-FKS

 

Stock air filter element? Clean the MAF?

Do those have the iridium 100K mile plugs or the standard kind? If standard the interval is usually 30K so that may be something to check.

 

Could you clarify something? You said you drive an MT but then you said it idles rough "at a stop while in drive." You mean in gear? Foot on the clutch? If you put it in neutral and take your foot off the clutch does it change?

 

I'm sorry that is a typo on my behalf, I have an automatic transmission, thank you for pointing that out.

i just replaced the air filter, so I'm pretty certain that is not the issue. I'll take a look at the MAF and see if it is dirty, first I just have to get my truck back and locate it! I appreciate you bringing that Up!
It sounds like I have a few different things to check out. I'll report back if they find anything or if I make any progress! Thanks for the input, everyone.

 

I thought that might be the case. Unfortunately I have no insights to add if it's an automatic!

 

Wait a minute... is it only in drive? What if you'r in neutral or park?

 

The idle is roughest in drive at a stop, but can also be felt (lesser) while in park and also neutral.

 

Is it still rough if you turn of all climate control items like the blower and the compressor?

 

Check MAF sensor?

 

You should not need a fuel injector cleaner, or even worst, be charged for one if you have been maintaining the vehicle properly and as you mentioned you replaced the air filter element therefore you should be golden in that respect.

Having said that, have you been using top tier fuel, or have you recently changed the fuel you used to fill it with? moved to higher/lower elevation, or fuel out of town?

I would not think your spark plugs would be bad either as that should show on a scope/scanner.
But I would check to make sure all clamps leading to the air filter housing, housing itself, to the maf sensor are all good & tight.

I would clean the maf sensor with approved for TOYOTA maf sensor cleaner. I would also look for any vacuum hoses that maybe loose, and if the idle get worst or better when you step on the brakes then bingo, you solved the problem, have your dealer check the booster and vacuum valve for replacement as needed.
If all that's fine, there maybe loose intake fasteners or defective gasket seal in throttle body. You can spray that area with some carb cleaner to see if it smooth out or changes.
Also depending on the setup on you engine, you maybe able to gently move the throttle body to see if there's any difference in idle and that may also tell you if there's a bad seal/gasket or loose fastener(s).

Let us know if you find a solution on this normally very good and reliable power-plant.

 

Yes I tried to see if that made a difference, but it doesn't seem to effect it at all. Good point though!

Thank you for your in depth input, as I am a little lost here and appreciate all the components you have suggested I take a look at. I will definitely be checking all of these tomorrow afternoon. I will also try cleaning that sensor out. I transitioned to 93 octane after my 20,000 mile service after draining the tank as much as possible, with no difference (now at 24.5k). I just got the truck back from the dealership, and they said that everything which they check seems normal ( and as expected it fired no codes). They did however say that my throttle body was dirty, and they cleaned that out for me. They said that the idle is a 'natural characteristic of the truck' and that the vehicle has simply 'broken in' since when I got it new, and that this experience is 'typical'. Sounds like bologna to me, so I tried to argue that it couldn't possibly a typical experience or people wouldn't be buying them, but other than that i didn't know what to say so I took the keys and left. The idle still exists, so i'll be tackling the suggestions i received here and see how that goes. Ill make sure to keep everyone updated. Thanks!

 

2.7 doesnt have that problem

 

Another thing you may want to look at and is DIY friendly, is to open the hood and lift the red cover on your battery and look for any signs of corrosion build up on both terminals, then give each terminal a tug to see if they're good & tight.

Today's highly computerized vehicles need good, solid clean connections to work at their peak and as intended.

If you find corrosion build up, you can clean them yourself with care, or take it somewhere you trust but ask them to save the computer memory and media settings as this can create drivability issues for a time until the ecm re-learns all the parameters and adjusts to the wear state of various components.

I recently performed battery maintenance on my 3.6L with over 30k miles, and saw a noticeable improvement in idle quality.
Below is a more detail guide on battery cleaning maintenance procedure:

https://www.tacomaworld.com/threads...ce-101-day-for-me-today.532182/#post-17059483

 

Wow that it another interesting angle I hadn't considered. I will look tomorrow and see if my battery is in decent shape, but I believe that the negative terminal had some corrosion. I'll take a good look at the thread you posted. Thank you!

 

I'm having an idle issue as well. My idle speed will drop in a cyclical manner while stopped. It will drop below 500rpm for a second or two, then rise back up to normal. Wash, rinse, repeat. When it drops below 500rpm I get the vibration. Very interested to see what you find. It's not associated with the A/C cycling, and shouldn't do it with the A/C cycling anyway.