Rough Idle?

iv got an 08 4.0L 4x4. every so often, once every day or two, i get a weird rough idle. not something that would make you think wow, something is wrong. but definetly noticeable. anyone else experience the same thing? iv got almost 5k miles and threw fresh Mobil 1 in at 3500. it seems a little rougher if iv got the a/c on. i just expected perfection from toyota...am i being too critical?

 

ive noticed it when i turn my A/c on

 

I was actually looking to post the same observation. The idle is most definitely rougher than I expected for a Toyota......

I only notice it on occasion....it's not a steady issue.

Part of me is glad that others are experiencing the same issue....I know that it's a quirky Toyota issue.

 

Not that its rough....

But if I'm sitting somewhere (stop light, drive-thru or whatever), the truck ramps up to 650ish for like 10 seconds, then drops down to 540ish for a few seconds then back up, down, up, down.... (I have a scangauge and exhaust and can 'hear it').

I don't consider it anything wrong. Just weird.....no accessories on except maybe the heat/fans. And other times just turning fans on - it'll ramp up in rpm's.

 

Just had my 07 in the dealer for rough idle. It seems there is a problem with the cam timing position switch. They ordered me a new one. Hope this fixes the problem

 

when i had my 06, and took out the secondary air filter.......my idle was smoother. most will say that removing the 2nd filter doesnt do anything, but i know for a fact that my idle seemed smoother.

 

Did they replace your cam position timing switch? I'm curious as the dealer can't find what's wrong with my 2011 Tacoma as its underpowered and idles rough. Its not throwing any codes so they don't know where to start looking.

 

mine also seems to run a little rough at times, but i'm also over do for a spark plug change

 

I am curious about the cam timing switch. My 07 has idled rough for a while now. My mechanic noticed it when we were getting ready to replace plugs so I hoped the plugs would do it. No difference.

I just put new, more aggressive tires on and gas mileage has dipped. Wondered if it was all the tires or some efficiency issue coupled with the rough idle.

 

mine has started doing this more often now. Its weird because half the time it is happening, I can turn my vent blower all the way up and the idle is a lot rougher and then I turn it down and it almost goes away. The other half the truck is idling weird, the vent blower has no effect on it.

 

I know this is an old thread, but my 07 4.0L engine has been doing the same thing as described above ^^^
Was wondering if anybody has found out what the problem is or if there is a way to get the engine to idle smoother again. I recently changed the spark plugs and checked air filter ect...
Engine has 143,500 on it.

 

I am having the same issues with my 2007 Tacoma, has anyone resolved the issue?

 

Just forwarded this to a buddy with similar issues. Thanks

 

Low idle while in gear on my 07. Drive or reverse it sits at 500 to 600 and neutral sits at approximately 800. Changed plugs last week no help. Gonna clean throttle body next... any answers yet?

 

Clean or replace the IAC (Idle Air Control) valve

 

My 2004 2.7 does exactly what everyone has already pointed out. I'd say it is normal with any real mileage at all. I'd suspect the EPA, not Toyota. I'd also agree with this last post by tan4X4 that it is probably the IAC since that is what controls the idle along with other "gadgets". I really don't worry about it since I think it's normal but I'll be cleaning/replacing my IAC someday since my truck has 162,000 miles on it. My personal opinion is I'm not going to worry about it unless my engine starts stalling. The up and down idle I experience just like everyone else is nothing but the sensors, computer and everything else doing their job to reduce emissions. It's just more noticeable as the various sensors and electronics age.

My personal opinion is that all these various sensors and electronic gizmo's on the newer vehicles may still work and throw no codes but as they get old their performance deteriorates. The real problem is? What gizmo do you replace if you think it might be getting "old" but still working. That's the problem since there are so many that affect the engine performance on even something as simple as the 2.7. What I will do in the future is just start replacing all the sensors and electronics such as coils, injectors etc., etc. with Toyota parts as the miles on my engine continue to stack up. I've only got 162,000 at this point so I have plenty of time to start gathering parts.

There are "tests" anyone can do with the right equipment so you can "test" a sensor or a coil or anything else but that would be a real PIA. I've read through the procedures for some of those tests and I'm certainly not going to spend the time performing them because I don't have the time. Anyone can though and the "equipment" is cheap.

We can ALL thank the EPA.

 

digging up an old thread. I currently have these exact problems. Did anyone find a fix? 2008 2.7L

 

clean MAF sensor and throttle body, check/change spark plugs. There's no other real adjustment on them unless maybe you have a vacuum leak somewhere.