Question: as long as had the truck I have never pulled the EGR valve out and cleaned it is it possible that it might be adding to a low idle issue? Yes I have both the sticky high idle and the ever infamous low rough idle problem at the same time. So I while I'm under the hood maybe I should pull it out and clean it too. Going to do the vacuum leak check on the throttle body too.

 

The EGR should be closed at idle, it only opens on acceleration and cruise. It is possible to have one stuck open which would make it stall or run very rough at idle.
The idle mixture trim is also adjustable, but sealed under an aluminum plug, see post #83 in this thread about it. Adjusting it will smooth out the idle, as long as there isn't another problem causing it.

 

I think it's a definite possibility so I will go ahead and pull it, I also dropped in b-12 chem fuel treatment today. With that said I found a small drip coming from the upper radiator hose which probably just needs the hose clamp tightened.

The EGR valve let out a cough wheezing chirping sound about a week ago that was pretty pathetic sounding. But before I went to pulling it wanted to hear back from you first.

You are talking about the AFM adjustment aren't you? It's been on my mind too but I wanted to check everything else first to make sure I had no other issues in addition

 

I've never heard an EGR make noise by itself, are you sure it wasn't a backfire?

 

Nope it was a definite wheezing chirp noise haven't heard it since

 

I've seen that happen when there's a backfire in the intake, or the engine dieseling (running on) when you shut it off, it can even push the EGR valve open and makes that noise when it does that. There's several things that can cause it, but if it only happened once it could have been shutting it off with the sticky throttle symptom you described.

 

Thing is it started with the low idle issue right after that... Strange I know but that was the order it happened in. Pulling the throttle body off right now to double check all the ports and the butterfly is clean

It was dirty but no obstructions going put back together in the morning it's threatening to rain and gasket is still a bit wet.

 

The noise only occurred on start up

 

Drove out of town again today, my 4Runner will do this warm start scenario occasionally. It's been unseasonably warm, so I took some wires with me. Went to start it after I got there and it sat for 20-30 minutes and it did the low idle not wanting to run thing. I shut it off and grounded the wire for the switch for the fuel pressure up. It started great and idled up, approx. 1100 RPM. I let it idle for maybe a minute and took the ground off and started and drove off. I'm going to wire in a switch and just operate it manually from the cab. I put a new aftermarket switch in, the old one didn't work either. These things are fickle, that's why there is a service bulletin.

 

Wow kinda strange stuff.. Toyota. Glad you made it was OK
So it's a bad fuel pressure switch ground? Mine won't start unless I let the fuel pressure build up a little always been like that never thought much about it, which leads me to wonder about my fuel pressure regulator.

 

It's the FPU (4WD) switch not closing and providing the ground when the engine is above a certain temp.. It's labeled Water Thermo S/W (4WD) in this.

 

What year is your truck? Where is your switch I thought you said it was in the cab. Far as I know I have sensor switch but the only one I know of is in the front of the block there are actually two of them one green and one brown. What does that little bugger look like, can you put up a pic?

 

My 4Runner is a 1987. The switch in the cab is what I'm going to wire in to operate it when I need. This switch is by the throttle body. Here I got a pic. I moved the vac. lines, it's between my thumb and forefinger.

 

Ok might be the same operation but just located in a different spot mine is an 89 and the switch is in the front, could be one possible cause for my issue but I don't think so. I have seen other folks hard switch that one. But mine starts right up then the idle just drops and tries to die out until I hit the gas then it runs just fine. Or the when it idles up it wont come down unless I tap the gas. So today I pulled the throttle body off and cleaned it up and put a new gasket on it. Tomorrow I remount it and check it for vacuum leaks, for starters.

 

I think the ones you are talking about in front, are the water temp sensor for the ecu and the cold start time switch. Mine are there too. The temp sensor for the gauge is further back and down in from the switch in the picture I took. Took me awhile to locate all these.

 

I don't know then if I do, I haven't found any yet but I will keep my eyes open for it. As I said before though my temp gauge doesn't match up to the wiring so If it's there it's probably not hooked up.

 

Over the top of my brown temp sensor in the front of the engine is a nut with a white plastic tower with a black cap on it, it also has two rubber hoses coming off going back into two metal vacuum lines. What is that? It's a little over an inch tall. I have tried to look it up but can't seem to get a straight answer anywhere.

 

Sounds like you're describing the vacuum tee on the intake manifold. Or a thermal vacuum switch.

 

That describes it for sure can that be a problem if it's bad

 

Is it mounted in a water passage or an intake passage? If it's mounted in a water passage it's a thermal vacuum switch, which only allows vacuum to flow when it gets to a certain temperature. Yes, they sometimes go bad.