rough idle

Ok, i have a question for the techs, or really good shadetrees! 04 Tacoma prerunner dc v6. 166k. Just replaced within a hundred miles: Plug wires, ngk (didn't do the boots on the coil pack side due to the understanding that id have to replace the coil packs which seem fine) plugs, oem denso dual electrode, fuel filter. Within 3000 give or take: Oil, oil filter, air filter (switched from k&n to regular due to possibility of oil getting on the maf) maf cleaning including oem air induction tube, throttle body removed, cleaned, reinstalled, new pcv valve. Wiped out the inside of the intake manifold as far as i could get my fat in with a rag and solvent. New auto tranny filter and fluid. The truck has a rough idle when in drive after its been warmed up, even before all the work. Not james bond "shaken, not stirred" type rough, but enough to switch to neutral when stopped. All the work done changed nothing but piece of mind that i have new, or really clean parts. Im debating seafoam in through the pcv hose going into the intake. Ive also seafoamed every few fill ups. What would cause the rough idle?
Ive owned it since it had 2716 miles, so i know how its been maintained and that has been well. Not %100 perfect, but pretty damn good. And always by me. I should mention that it still has the original timing belt, knocking on wood! No cel either. Any and all ideas are appreciated. Thanks.

PLEASE DON'T TURN THIS INTO A SEAFOAM + OR - THREAD

 

Do a search for Toyota idle air control valve cleaning. There are lots of pictures and videos online showing how to clean it. It's common on Toyotas for the IAC to get gunked up and not open all the way giving a rough idle. It's similar on different Toyota engines so any good thread or video will show you what's involved.

 

So did all the problems start right after the cleaning? If so I'd say Dr. Z is right on point.

 

The rough idle was there before i did the tune up. I originally took took the throttle body off to clean the iac, but was unable to locate it. From what i remember, 2004s don't have one or it's in a different place. I even bought the gasket! But there was no part resembling the iac. If someone could take a pic of the iac on a 2004 that would be awesome. Im gonna do some research.

 

So after putting my vin into toyotapartszone.com it basically says i dont have an ide control valve, or aka iac... Besides visually inspecting the motor mounts, how could you determine if they are bad?

 

A few years ago i replaced a dog bone styled upper motor mount on my g/f mid 90s camry v6. But that was obvious. The rubber was all blown out and the motor would clunk under rapid acceleration. I know cars are weird, especially electronics. Apparently my model has no iacv or egr. Im still researching. But not coming up with much. Maybe just seafoam it! Like i said, its a very slight rough idle. Most people probably wouldn't notice it. But because ive owned it for so long i can tell. Thanks for chiming in.

 

Are you sure about this? RockAuto shows one for the 2004 3.4.

 

When i removed the throttle body a few months ago nothing resembled that part. I just looked up rockauto and see they have one listed. I think ill call the dealership. Ive

 

so you didn't see anything under the throttle body with a bunch of hoses connected to it that looked like this?

http://www.ebay.com/sch/i.html?_fro...TRS0&_nkw=toyota+3.4+IAC+&ghostText=&_sacat=0

 

Ok, so i just popped the hood, looked all around the tb. Nothing resembling an iac. Called toyota to confirm, and after running my vin they say my truck doesn't have one. However in preparation of installation of my oil catch can that will go on next week (its really just a fun little project i wanna do, if it works yea! if not, oh well) i was toying with the new pcv and the new grommet fell apart... Maye that's the problem. Will report back on that shortly. Off to toyota for a new oem grommet. And i do recall reading somewhere someone hooked a catch can to his 3.4 tacoma and it helped smooth his idle.

 

well 3.4 is very different im sure but on my 4 cylinder the IAC cant be seen at all, its completely underneath the TB and at best you just see the connector plug on the bottom of the TB so you don't even know what it looks like until you remove the TB and turn it over and there it is.

maybe you don't have one (some newer 1st gens don't) but there is an idle air mixture controller device or sensor somewhere so you need to discover what your engine uses for this and check/test that

 

Bear with me, im gonna try and upload some pics. This will be my first time. As you can see no signs of an iacv. In the last 2 pic, what are the circled items? When i took of the induction tube i noticed some thick bbq consistency sludge. Is it a second pcv? The hose goes from the metal tube circled across to the plastic deal in the induction tube.. Pardon my terms, if they are wrong!

 

im not saying that's your problem but this picture shows a small metal vacuum line disconnected, something is supposed to be connected there.

also some of the other hoses show cracks so you may have other vacuum leaks going on so its best to replace all your lines since its not just one that's going to be dry rotted and cracking

cant realy see what im looking at here but is that another open connection with no hose connected to it?

plus the pcv valve gasket seal is important and can add to your fast idle issues if its leaking

you will also have a small 5/16" or 3/8" water line feeding the egr valve so it only opens the egr after the engine is warmed up

I think you have some lines mixed up hooked in the wrong places or missing and things are not connected.

I think it best to compare yours with someone elses 3.4 engine so have a look at youtube videos or find a friend with a 3.4 and compare how everything is connected

 

Cool the pics work! That tube that isnt hooked up was removed just for the pics. I reattached the hose. Just curious what it is cause when i took the intake tube off for pics i saw the residue inside the tube right about where it clamps to the tb, it almost seems like a second pcv. Im sure its unrelated. When i did the pcv original a few months back, i sprayed carb cleaner all ove the motor to look for vacuum leaks. I know some of the hoses are cracked, but they "seem" to not exhibit any leaks. But thanks for pointing that out..
To be clear, my issue isnt a fast idle, its a rough idle while in drive, say at a stop light or drive thru... It still idles in the correct rpm range..
Just re-read your post keakar. The little metal tube bolted to the manifold has always been disconnected. I think its probably there for other applications, like different cars. Its never had vacuum. Or pressure.

 

you will need help from someone with a 3.4 engine, I have nothing to reference your questions with but the first step I would do is replace all the lines so you know nothing is leaking or blocked up anywhere.

as to that gummed up line, maybe its a vacuum line from the manifold that's sucking up oil mist because the pvc wasn't working right but im purely guessing.

 

No worries, at least your trying!

 

Send me APM tonight I'll check the FSM, though it's for an 01

 

Did you look under the "Fuel Injection System" section at toyotapartszone.com? That is where the IAC is listed. (Valve Assy, Idle Speed Control(For Throttle Body))

I thought all cars in the last 20 years had an IAC. How does the computer control the idle otherwise?

 

Every where im looking there is no iac for my year. And as mentioned before ive had the tb off, and didn't see anything resembling an iac. I replaced the pcv grommet to no avail. Im just gonna seafoam the fu€ker... Ive seafoamed my 94 400k honda accord with good success. Maybe the catch can will make a difference too.

 

Just to clarify. All hoses, lines, wires are al hooked up correctly. The truck runs good. Idles at 750 when in neutral. Ides at 650 with brake on and tranny in gear, its just a very ligh rough idle. As mentioned above most people would probably dimiss it. Im wondering if its just cause ive never done the belt or valves...i do appreciate all your input.
One other thing,apparently these ttrucks dont have an egr valve either..