Bad Shake at Idle When Warmed Up 2.4L **UPDATE POST 16**

Did you take it to the dealership for the valves or??? Also what did it run you cost wise to do the valve check...out the door?? Been needing to do mine(two of em)...

 

It was around $300 overall and this included the pucks that were needed. I didnt feel like tackling it myself. I took it to an independent shop that specialized in Toyotas.

 

Is that on a Gen1 or is that on the pre 95 models? I know there is an idle air control but it is automatic adjusting and I dont recall seeing a screw on it. I adjusted the stop which sets the butterfly position.

 

the actuator is the ONLY screw mine has, there is no throttle stop screw that I see anywhere
that's why I was hoping to see a picture of what you were talking about

 

I'm sure yours has what's he's talking about too. On the deal the throttle cable wraps around at the TB(what you'd grab and turn to rev engine from under the hood) there is a screw or bolt or piece of all thread that is adjustable on that piece. As soon as you open the hood and look @ the TB its staring right at you. You can't miss it, its behind the deal the throttle cable is fastened to.

 

no, all mine has is the set screw to adjust the actuator which by accident would also raise the idle speed if you turned it far enough but this would alter the actuator speed adjustment beyond where it should be.

having the typical rough idle issues as most, I first thought this was the idle speed adjustment until I saw in the service manual it said NOT to use this actuator set screw to try and adjust the idle speed or the actuator speed setting will be much too high when it is engaged.

the idle speed is adjusted by the IAC only and is based on engine temperature, according to the manual

now all that said I was thinking of using the actuator adjustment screw to slightly raise the idle anyway because im only looking for 100-150 rpm increase and think raising the actuator speed by that much wont be a huge jump but I was really hoping there was indeed a dedicated idle speed adjusting screw somewhere.

I think this is a better then nothing solution that's for sure.

 

No.

 

there that sucker is!

thank you

mine wasn't visible until I cleaned the gunk off of it but I still don't see how I didn't notice that was even there. its so obvious and stands out now that I know where it is .

still not easy to make it out so I assume that's a 10mm nut to hold it and how do you turn the screw? is that Phillips or an allen screw and how do you get something to turn it? is there a certain way to come at it? from front (left side of pic) or back (right side of pic)

just goes to show there is really a lot of missing info from cheap repair manuals because while mine said all that about the actuator screw setting it never said the idle set screw was right behind it so by the manual not saying anything about even having a throttle set screw, I wrongly assumed there wasn't one.

 

ok, answered my own question, sort off.

the allen set screw I used an 2.5mm allen wrench and its adjusted from the left side, the lock nut I used an 8mm but both are a sloppy fit so the nut may be 7mm (which I don't have) but the 8mm does the trick. and the set screw might actually be a 3mm but the one I used didn't fit so but maybe its just got rust in it and it really is a 3mm.

just wanted to add this if it helps anyone.

 

You should only have to turn it very slightly to make up for the wear. Anything more than that and you have other issues that you are masking

 

had to turn it a complete turn to raise the in gear idle back to 750 where it belongs.

it was sitting at 650 and very rough idle, now at 750 its still a rough idle but much better.

im sure I have other issues but the low idle was the most bothersome to me.

I think I have IAC and TB cleanup in my future to solve my slow acceleration stumble/stutter as though its not getting enough gas

upon further thoughts the allen wouldn't turn it after it had resistance on the screw so I cant really tell if its a star drive or allen drive screw as its impossible to see in there so I grabbed it with pliers and used the nut to turn it while lifting the throttle arm.

 

I used an allen wrench

 

I just pulled my throttle body to clean it and found the idle speed allen screw was blown out completely with nothing left of the allen socket, it was just peeling open so some jack leg before me must have cranked on it without loosening the lock nut or tightend the lock nut by cranking on the set screw, either way it was trashed.

once I had it on the bench I could also see the idle screw wasn't even touching the throttle when cold which I wasn't expecting so its important to never adjust it with a cold engine.

I replaced the allen screw with a much easier to adjust Phillips head screw from ace hardware (5mmx25mm) and its so much easier to adjust now instead of trying to fight with a small allen wrench.

Toyota designed it for allen screwdrivers but most people don't have these so if anyone out there wants to convert theirs to a more logical solution go to the hardware store and buy a 5mm x 25mm Phillips screw to replace it with.

I replaced both the idle screw and the fast idle solenoid adjusting screw and I am looking for a tension spring to fit these screws so I can also get rid of the impossible to get to locking nut so if I find one I will let you know.

 

Yes, I adjusted it while the truck was hot and in gear with someone on the brakes

 

Going on close to a month and the truck still idles perfectly so I think it was the answer

 

So where is this screw? I have a 97 tacoma 2.7 auto 4x4

Done everything on the truck still rough idle, I read that it needed a ‘revised ecm’ as in 1999 toyota had a tsb (technical service bulletin) to update the ecu which stated ‘would improve engine smoothness at idle’

 

Does anyone have a pic of what op is saying? If i’m getting this correctly the butterfly inside the throttle body in which lets air inside has a ridge that when at a redlight only a lil air goes through for it to idle at set rpm, but after time the ridge gets worn down in which less air goes through and you get the rough idle, do i have that correct? And his solution is to set the stop screw at idle at a redlight for the butterfly could open slightly enough for it can be at around 750rpm for it can idle correctly. Ima mark my set screw and then adjust and see whats up,

 

I believe the “ridge” he’s talking about is at the lever outside the TB where the set screw contacts and sets base idle on the butterfly or main air valve, most of the time the TB wears out and the idle increases. I have never seen this ridge and therefore cannot verify it’s existence but you can’t hurt anything by adjusting the set screw. Like you said, keep track of adjustment so if it doesn’t work you can always go back to where it was.
Any chance you post back what the outcome was?

 

yes I will go look at my thread “rough idle gremlin” everything under the sun has been done, you name it ive done it, surprise me.