Low idle, rough idle, CEL

56,440 miles 2017 TRD offroad 4x4

No power issues or fuel consumption issues before this.

*edit-codes as follows*
Codes are all fuel ratio;
p11EB00 bank 2 air-fuel ratio imbalance
p219B00 bank 2 air-fuel ratio imbalance

tech noted "cylinder 2 and 6 misfiring when direct injection is being used"
*/edit*

So yesterday while driving to work it started giving me a rough low idle when I stopped at a light, first time. On my way home same thing then threw a code. Took it to the dealer at 8am and they called aroun 1:30 and needed me to approve 2more hours of diagnostics. Just called me at 3pm and said "everything points to carbon buildup" And wanted to charge me about $900 for plugs and I assume top engine clean as well. (over 1100 with diagnostic fee added)

I've had a lot of cars and only at like 200k does the carbon buildup really get noticeable but none have acted like this and add to that this truck gets only the best gas and I even add 1k and 3k chevron additives.

I didn't think to ask what code it threw while on the phone so we'll see if it's on the report.

I mean I could see bad plugs causing a rough idle for sure and the plugs do have 56k on them...but it literally happened all in one day and it hasn't lost power or fuel economy and I don't normally replace plugs before 60k and have never had an issue, hell I've gone 90k before (iridium NGK's are what I normally use). Hoping it is just the plugs and the "carbon buildup" was so the tech didn't feel like an idiot for wasting all day chasing a maintenance related issue. I'll try to get the code and take a pic of the plugs when I replace them later today. I'll have a peek down the throttle body as well.

 

Could be map sensor & throttle body needs cleaning

 

? Wtf ...try running some sea foam first . See if it fixes it . Low miles to need something that extreme top end cleaning.

 

bad fuel... try a tank or two of mid-grade, or premium fuel... I've noticed my idle is noticeably smoother running premium.. I also rev up my engine from time to time to clean out the gunk, I also clean my throttle body, and intake with every oil change.

 

My paranoia says everything points to dropped valve seat, carbon build up sounds like let's push this truck outside the warranty window and hope it doesn't blow up

 

Yep, sounds like the same issue that has hit some folks requiring headwork. I would definitely ask what code it was throwing. If it has anything to do with a "misfire", I'd request a 2nd opinion.

 

"Everything points to carbon buildup..."
That sounds definitive and reassuring...
They're guessing.

 

typically rough idle can be due to a couple of reasons. 1 bad fuel, bad timing, or carbon buldup on sensor/IAC.

 

I know...
Don't mind me.
I'm just a jaded skeptic.

 

What was the code?

For an engine with a cleaning cycle it sounds fishy too me.

 

Weird, I thought the Tacoma engine had direct and port injection? Even so, there should not be significant carbon buildup after 3 years.

The only way they could diagnose this is with a borescope, so there should be pictures of the buildup.

I agree, this is not normal and even if it is carbon build up, there’s a bigger issue.

 

Sorry to hear about your troubles OP. And If you’re using brand name top tier fuel, done regular maintenance such as oil changes, air filters, your truck should perform good as new.

That being said, It sounds like the failing fuel pump that is under recall on some vehicles. And of course I’m sure they already checked that and ruled it out?

Never the less, I would try another dealer, one with good recommendations.

Best of luck

 

Is your truck on the fuel pump recall list?

 

Almost as if they asked the magic 8 ball

 

No lube. . Edit: and I’m no help, either. Sorry. Edit, again: meanwhile back in the managers office

 

I recalled reading something about this and when I googled that there appears to be thread about the cleaning cycle here at TW as well. I've never heard anything that I could tell as far as a cleaning cycle lol..?..I think fuel pump been the best guess thrown out there.

 

@Bcjammerx

OT, but your name is super familiar. You a CB7T guy?

 

Sorry for the late reply, was at work waiting to get off to get the truck
Codes are all fuel ratio;
p11EB00 bank 2 air-fuel ratio imbalance
p219B00 bank 2 air-fuel ratio imbalance

tech noted "cylinder 2 and 6 misfiring when direct injection is being used"

They apparently cleared the codes as the CEL is off but once it warms up and I come to a stop I have to give it a little throttle to keep it just under 1k and it stops it from shaking though I can still feel it misfire

Whenever I check my truck isn't on the fuel pump recall though it's year has been recently included, I would assume they checked but might be making an ass of myself doing that...I can't say whether they did. I believe I saw that it already had the crank sensor tsb too before I bought it.

I agree, carbon buildup to that extreme is unlikely due to this truck being only 4 years old and 56k. And I forgot that toyota markets the direct injection as being self cleaning so that adds to me already questioning carbon buildup as a cause. Plus I only fill up at phillips, chevron, or shell nowdays...all top tier and I have been adding chevron additives on top but not religiously...I shouldn't need to though, that should be overkill.

Luckily I do have a "certified pre-owned" 100k powertrain from Toyota which should cover things like injectors/valves/sensors that are directly connected to the engine but I'll need to re-read it to be 100%. Plus I'm still under 60k but barely. But I really hope it's not about to drop a valve, I did see those posts a while back.

I'll be replacing the plugs tomorrow. I'll also do tb and intake runner cleaning, and running some seafoam through the intake...good thing I'm almost due for an oil change. I'll get a better idea once I see the plugs. If it does it again I might not take it back to them, I only took it in because I have the warranty and that's were I bought it. There's a toyota dealership in almost every city around me...I would like to think the warranty is valid at any toyota dealership. If it happens again or I can't get it to stop tomorrow I'll be making some calls for sure.

 

I was until my accord got stolen (well sorta stolen)...I actually still have a6 intake/ecu parts and bisimoto forged rods, never got the chance to install them

 

Awesome! I’ve been out of the game since 2007, but still visit the site probably once a week.

Sorry to pull your thread OT.