intermittent rough idle

[01thunder]

park and neutral, no problem. but when in drive and or at a stop, it starts idling a bit rough. then it goes away. could be 2-3 days later, it happens again. no CEL's and all maintenance is up to date. any ideas?

 

[fourwd1]

There could be an error code stored even though the CEL isn't on, it may be worth having them scanned, especially when it's happening.

 

[01thunder]

doesn't have any. i am leaning on maybe a fuel pump or injector or cat going bad?

 

[dhalsey]

doesn't have any. i am leaning on maybe a fuel pump or injector or cat going bad?

I have had three vehicles with the 3.4 in them. Once you get high in miles the injectors get clogged from bad gas. I sold my first truck because of it. My recommendation first sea foam it and then put a bottle of lucus oil fuel treatment in for a couple tanks of gas. It will work. Report back after you try it.

 

[BlackCat914]

In intermittent weird issues like that, I tend to lean towards electrical stuff. I'd be looking at MAF values and things like that, which will make it tricky to pinpoint. Usually, in my opinion, if an injector is clogged, it's not sometimes clogged. In my experience, it's usually a chaffed wire that makes intermittent contact with metal or something along those lines and causes your issues. They're a pain in the ass to find, especially intermittent issues.

 

[Kenjan]

TPs air valve

Carbon build up

Also has ur mpg changed just abit??

Chk ur o2 sensors
Could be a buildup n the PCM readjusts the fuel map
Till another build up

Aka--clean ur air intake and TPs system

 

[01thunder]

i have been sea foaming since i bought it, i'll try lucas. i have also replaced and cleaned components; O2's, tps, maf, etc. mpg's are the same as well. i will try the fuel additive first and take it from there. i don't want to take it to the dealer for service for obvious reasons.

 

[kball]

When it happens is your idle speed dropping to low? Maybe that's why it gets rough. I would think maybe your IAC needs to be cleaned.

 

[Boosterror]

Mine does the same thing but it only does it once in a blue moon

 

[Kenjan]

Yes that could be it IAC

Rpms dropping to far

 

[01thunder]

no rpm drop.

 

[Kenjan]

Kinda sounds like ur cat

Does it do it at full chat??

As in wot --pushing hard

Not like bad gas or anything but say when the cruise
Is on at 75 ??

Does it do it at all at first start up?

Or after say 15+ driving

 

[01thunder]

Kinda sounds like ur cat

Does it do it at full chat??

As in wot --pushing hard

Not like bad gas or anything but say when the cruise
Is on at 75 ??

Does it do it at all at first start up?

Or after say 15+ driving

no to all.

 

[ABOZEYAD]

01thunder .... i have the same exact word by word problem and i have been searching like crazy all over with no luck... no cods stored or showing. i cleaned
everything that may cause this , sea foam it like three times, tried all the additives .. still no luck.
please update me if you fined the source of the problem.

 

[akbass907]

I'm having a very similar problem, but it happens when I'm in any gear, rough idol, drop in rpms when at a stand still. Not sure what to look at, thinking MAF in my situation but not sure. Very depressing after throwing a grand into a newer tranny.

 

[BrianIna]

Has the idle problem been solved yet?
I have a 2018 4Runner with 50000 miles. I can feel the rough idle while sitting still in gear or park. You can feel it in your seat. It reminds me of an irregular heart beat.