Rough Idle

Hi everyone,

I am new here. I have a 2005 Tacoma with 200,000 miles on it. I have had a few issues lately and can not figure out the problem. I recently had a few misfires, I changed all the plugs and all the coils. That helped with the misfires but now my truck idles really rough. It sounds like it is cammed out lol. I stared with cleaning the MAF and that seemed to help a little but started up again. So, I bought a new MAF and the same thing happened again. I tried to reset the idle, but still no change. Has any had the same issue or can point me in the right direction?

Any and all suggestions is appreciated.

Thanks,

 

Throttle body cleaned? Check for codes?

 

Sorry to hear about your troubles....by the way. Welcome to TW

What are common reasons my Toyota Tacoma has a rough idle?

While there are a variety of reasons your Toyota Tacoma has a rough idle, the most common 5 are a vacuum leak, an issue with the spark plugs, or a problem with the ignition coil and or dirty fuel injectors and the PVC valve.

Before you wildly start to just change parts out; I would scan the truck for any code faults. Some parts stores I've heard can and will scan your truck for free as well. Do you have a maintenance manual and or any track records that will help you (us) in our quest to rectify you rough idle

Keep us all posted and good luck! Go Team TW ...

 

mine idles rough but cause i got a leaky head gasket.

 

Check where the air intake fits into the fender well. If the foam is worn then the part will vibrate resonating sound to the cab that sounds like a rough idle. Replace foam with off the shelf weather stripping.

 

Check your hoses there’s a small hose behind the airfilter its a small hose it can easily pop off when you remove the air filter box

 

Thanks for all the suggestions and help. I noticed today that my check engine light came on so I will go get it scanned. I have sprayed sea foam but have not cleaned the throttle body. I did notice there was a little carbon build up so I will need to clean that. I will also check the hoses and make sure they are still intact. Have you guys ever had issues with a vacuum leak? I hear that’s a pain in the ass. What is the best was to diagnose that?

 

I had an issue where my filter housing wasn’t clamped properly after I changed my filter.. RIP

idled rough for weeks until I finally checked it out and fixed it.. purrs like a kitten now

 

I learned an old trick to find a vac leak......you can spray WD-40 around (mist) and if the RPM increases you are in the area of your vac leak.
Its just that easy....
Go Team TW

 

I am also going to see if they cracked my new plenum assembly when they installed it. I will be making a smoke machine of sorts (many of DIY examples on Youtube) to see if I have an intake leak or a vacuum leak elsewhere.

https://youtu.be/GOhl4r0GSiE

There has GOT to be a reason for this rough idle when the truck is warmed up.

 

I just got done checking for vacuum leaks on the top end of my 'Taco. The cigar method worked EXTREMELY well, that Harbor Freight pump smoked that cigar like no one's business and I got A LOT of smoke into the top end. I took a pic of the throttle body, I had it taped up well before the test, and you could see the tape ballooning outwards as I was pumping cigar smoke into the top end of the engine.



During the smoke test, I saw a lot of smoke coming out of the area where the blue arrow points towards. The electronic side control of the throttle body. Shouldn't this be well sealed and not leak?


I don't have a can of WD40 handy so I could spray under that to see if the idle increased while the engine was running.

 

Also, just got OBD2 Fusion installed with the 2018 Toyota Add On. The Veepak OBD2 adapter works well with it. A plethora of PID's to pick and monitor from. This thing is better than sliced bread!



Set up a dashboard with Misfire counts on all cylinders. Now I'll know if those coils are misbehaving (I am suspecting No #3 and #4 coils). Better armed with more data to bring to the dealer next week.