Rough Idle Occasionally

Try to document it with a video and bring it back to Toyota. Where are your RPMs ranging when this happens? Happening this often with such low miles would probably rule out atkinsons cleaning cycle? Does not sound normal to me, I think I've only experienced that once due to bad gas. For the past few months I've used 91 Octane, and have noticed better mpgs. Although, I do not think the gas is your problem.

 

I have a 2016 2.7L 4cyl. Its just what it does. I've spoken to a few Toyota techs. Both motors are designed to idle very low at full stop for emissions purposes. Mine idles somewhere around 550 most of the time. It's normal. Just enjoy driving one of the most reliable motors you can get.

 

Mine Idles a little rough occasionally. I'm not worried unless the rpm's surge and fall erratically. Then it goes to the dealer. When I press the go pedal, no hesitation. As others have said, nothing to worry about. Way better than that Ford POS that I had before.

 

Exactly. I don't particularly like how low it idles at stops, but I'm also not an engineer. Toyota has some real smart cookies who figure this stuff out. Much smarter than I. But any kind of erratic idle fluctuations and I start looking for vacuum leaks. I also own a modified Subaru STi that I just about daily drive. I know all there is to know about god forsaken vacuum leaks.....

 

Funny you say that cause I just recently bought a SR 4 cylinder from Enterprise lol. 11800 miles on it, got it with a full tank. Started doing this after I filled up with 87 from BJs.

 

Gas from a BJs is your first mistake. Go to https://www.toptiergas.com/licensed-brands/ and stick to 87 octane like is recommended in the manual at any of these top tier retailers.

 

THIS

I also started using 93 octane Chevron fuel and I don’t hardly notice the rough idling much anymore. But I do if I use generic gas or anything below 93. So, good quality gas and higher octane should help.
This engine is good to run the higher octane. The manual states that 91 octane was used to test for factory mpg.

 

I'm curious how they got the octane rating. There are two different ways to get the rating that are popular. One results in 91 octane that is actually the American equivalent of 87. I know it won't change anyone's mind because octane preference is a religion but the science states to use the lowest octane that does not result in detonation for maximum efficiency and power.

 

The 91 octane they used is in the U.S.
These trucks are built here

 

Some are built here, some are built in Mexico.

You can put 91 and 93 octane in your Tacoma if you want. But time and Gain its proven that you are just pissing away your own money putting mid-grade and premiun gas in a truck designed and tested to run on 87. Its your money. You want to go light it on fire, have at it.

And the Atkinson Cycle only applies to the 3.5L.

 

[QUOTEBut time and Gain its proven that you are just pissing away your own money putting mid-grade and premiun gas in a truck designed and tested to run on 87. [/QUOTE]

That’s just not true. It’s stated in the owners manual that 91 octane was used to test for the mpg estimate.
I agree with you about the fact many engines don’t benefit from using higher octane, but know that all engines are not the same. Some manufacturers say that only 87 is recommended, some say only 93 is recommended. The fact is that Toyota says, for this engine specifically, “minimum of 87” is recommended and 91 was used in testing.
It’s not going to hurt anything to run 87, but the engine will run better with 91 or 93.

OP, try 93 octane for a tank and see if it helps smooth out the rough idle. It definitely does for my Tacoma. The Atkins system will cause some rough idling. That’s normal. It’s job is to clean the system while you are at idle.

 

91 was used for mpg testing not for engine function and longevity. That is based on 87 in almost every vehicle on the road. Also, most people dont actually know what the hell knock is or what it actually sounds like. Most of the people i know that have me come listen to their new vic because its knocking, dont have knocking. Its usually direct injection, port injection, atkinson cycle, etc making the noise.

You can run 91 or 93 in a Taco of you want and can swear it gets more power or better mpg, but you arent really. If you end up with 1-2mpg higher with 93 than 87, you arent saving any money when you factor in the cost difference.

Also, these toyota motors arent high compression performance engines. So any perceived performance gain is almost always attributed to the infamous "butt dyno".

Just run 87 and if it isnt running correctly, theres something wrong and thats why there are mechanics and warranties.

 

Communicating with memes. Jesus titty fuqing christ.

Guess youve never heard of companies using higher octane gas than what their motor was designed for in order to meet EPA mandated fleet brand minimums. You might squeeze a gallon or 2 more per mile out of it. But when its 30+ cents between each grade it doesnt do you any good.

 

Saw in the OVTune thread that Toyota has just expanded their fuel pump recall, check off that box first.

Https://www.toyota.com/recall

The owners manual weirdly states that you need to use a "minimum of 87". It's a weird choice of wording compared to most other vehicle manufacturers, but I think most people are trying to read between the lines too much. My advice is switch to a Top Tier gas station and if it's still having a rough idle after 3-4 tanks then try a higher octane.

https://www.toptiergas.com/licensed-brands/

If it's still acting up then know that Matt had said in the OVTune thread several times that some trucks he is working with are being stubborn and no matter what he has done they still have occasional rough idles.

 

If its bad gas and you have access to a live data obd2 reader tou can pull up something like dynamic advance multiplier and see what the numbers are doing. Not sure what its supposed to be at for a taco. I jst know its supposed to be at 1.0 for my subaru

 

I have discovered that my truck tends to run rough, especially in the winter (winter mix gas has higher amounts of detergents, and fuel stabilizers). and gives really poor fuel mileage, combined with cold air leads to poor running, and higher fuel consumption due to cold air density. my truck runs smoother/better on higher octane fuel. but the fuel mileage doesnt improve at all. so i leave it at that and put up with the rough running at idle for the winter.. I do think that the warm/hot idle (650rpm??) is set rather low, magnifying the effect of this... I can only imagine techstream could be used to program a higher hot idle.

 

Depending on where you live some winter blends can be up to 15% ethenol. That could mess with idle some.

I did an aftermarket CAI on my 2.7L for the ease of having a washable air filter. Ive noticed that in cold weather it runs a bit weird until its fully warmed up, then drives like the day I bought it.

 

Mine idles pretty rough, always been pretty annoying. Rode in my brother in laws 2006 4Runner v6 with 220k and it idles smoother

 

Late to this post but my Tacoma 1997 also idles pretty rough at stop lights but then sometimes it’s super smooth. I’ve changed out the fuel pump, fuel filter, VSS, Fuel pressure valve, and it seems to rattle worse . It’s got 160k miles though, so it’s made it this far.