2013 TRD OR - Rough Idle Diagnosis Help

Hey again TW word, looking for help diagnosing a rough idle!

152k 2013 Tacoma, recently purchased. Past owner maintenance has not been great forwarning…I’ve been having a rough idle and having a tough time sorting it out.
Things I’ve done to attempt to fix-
-Cleaned reoiled air filter
-Air cleaner vacuum line plastic nipple was broken off (no idea how long for..) I’ve fixed with a double-sided brass barbed fitting
-changed the spark plugs with NGK copper OEM (I double-checked all the gaps, all are right at 0.40),
-I’ve also used a generic Orileys fuel cleaner additive to hopefully help the fuel system out

What’s known-

-Air filter was SUUUPER dirty when I bought it a month ago

-When I bought the thing the vacuum line was broken off the back of the intake air cleaner. No idea how long this has been going. When I fixed this the idle got better but not great still (At idle the big douche bag towing dodge mirrors (removed) would shake)

-The valve cover gasket has a slight leak

-Seems to be a lot of valve noise from the drivers side of the engine. Almost a light knocking sound from cylinder.

-The truck wasn’t driven a ton by the other owner, sounds like it might have sate unused for a month at a time


things I plan to do to further help this problem:

-Clean the MAP/MAF

-Clean the throttle body

 

No codes set or pending?

In addition to your planned cleaning (be sure to use throttle body cleaner, not carb cleaner) I'd personally toss the oiled filter and go back to a paper unit. That won't fix the idle, but it will keep the downstream bits cleaning if any over-oiling of the filter should occur.

 

No codes, I just cleaned the MAP/MAF. Again a little cleaner idle now. But lots of valve noise from the driver side. The passenger side sounds great

 

replace MAF Sensor with a new one ! Keep old one incase ! Replace PCV valve also ! paper oem filter , get rid of oiled filter , it damages MAF sensor and cant be cleaned !

 

Thanks for the input guys!
I'm personally thinking its got to be an issue more on the fuel/vacuum side.

Does anyone know what about would happen if you left the vacuum line unattached from the back of the air cleaner box for a long time?

Wondering if it could have damaged my EGR valve or something...
https://www.tacomaworld.com/threads/08-egr-vacuum-solenoid.424397/

 

There is not an EGR valve on these trucks.

The vacuum leak would cause lean codes if it were bad enough.
Most likely the truck was compensating by adding fuel.

 

Update - I cleaned the throttle body (key on, motor off, chalked gas pedal to open throttle body and cleaned... It was really dirty) It holds an idle at about 550-600-ish! Truck doesn't shake as much at idle anymore, although the freaky valve noise is seemingly sticking around... I ran SeaFoam top end through the throttle body today to see if it could help, will update soon.

Thanks TnShooter , would you see value in running cleaner (Soafoam or equal) through the vacuum system knowing that a vacuum line has been disconnected for potentially years?

 

I wouldnt bother running seafoam down the intake, its only going to clean the upper intake which wont cause running issues, intake valves are going to be cleaned by the incoming fuel. The little line that broke off was for the fuel pressure regulator and would technically cause a rich condition if it was bad (less vacuum to FPR increases fuel pressure) but fuel trims were probably taking care of this within spec.

Get rid of the oiled filter. Get a paper type OEM filter.

Cleaning the throttle body and MAF well Replace the PCV valve while you are there should fix your issues.

As far as the noisy valve train... these 1GRs are noisy, and particularly on the driver side were the EVAP solenoid is that likes to click and echo on the intake plenum. You can mount the evap solenoid with some rubber washers to dampen the vibration to help with noise a smidge.

 

After cleaning the throttle body and MAF sensor, normal procedure is to also disconnect the battery for a minute or two. This clears and returns the ECU programming to the baseline settings. The idle speed setting for the throttle body changes over time to compensate for the deposits that build up.

When you reconnect the battery and restart: it may stall the first time and have a rough idle for a few minutes until it re-adjusts.

 

I may have missed it above, but I assume the truck has the V6: They're noisy. Valve-train clatter is pretty standard. Search "rod knock" and you'll get lots of hits. (It's rarely rod-knock.) The broken vacuum elbow (big leak) was probably causing most of the symptoms you were seeing. If you believe maintainance was minimal, and it maybe ran on no-name gas, check the PCV valve and add some Chevron Techron to the fuel. If nothing else, it will clean up the injectors and any valve deposits. I second the advice previous to ditch the air-filter and replace it with OEM. Snug down the valve cover bolts and see if that cures the leak. Use a light hand on them.

Welcome to the forum!

 

Thanks Williston and nd4spdbh! Mine is a V6
I plan to :
-inspect/Clean/Replace as needed the PCV valve today
-go to the paper OEM filter
-gently snug the valve cover for the leak
-I'll try that Chevron Techron, I did the generic Orileys fuel cleaner a couple weeks ago but more won't hurt lol.

Starting to feel like this is a pretty normal noise haha

 

Back on the rough idle!

I’ve noticed that after my short drive to work in the cold this winter my idle sounds pretty terrible whence it’s warmed up and I’m at work (see video example). No loss in power or anything at this point!

questions-
1. What would be symptoms of a bad ignition coil? See pics of spark plugs when I’d. Hanged them this summer
2. What warrants a compression test?

please the linked video for details
https://youtube.com/shorts/vPe9_qGyOxE?si=udPDaMyGYz5s311S

 

A bad spark will throw a code pretty quickly.... Have you tried spaying around the engine with starting fluid when it's idling rough? Basically a really good way to look for vacuum leaks. Hit all hose ends and the manifold seems and listen for a change. Usually very obvious.

Listening to your video all I hear is normal idling - but vids can be pretty hard to sort out...