Hey guys, I got a weird problem with my 3.0 and I'm lookin for some outside info to try & track down the problem. Thing is, after the motor is warm, it will sometimes idle low, sometimes 500rpm, sometimes 300rpm. Spec for idle is 800rpm and most of the time it idles there, just sometimes it decides it wants to idle low. The thing never hunts for idle, infact it is always rock stedy.....just low. So far I have tuned up the motor, plugs, cap, etc. I don't have any performance mods yet, so it can't be that. Checked & cleaned the throttle body, Just did a timing belt, but it was acting up before. replaced the fuel filter, PCV valve (real fun by the way) checked timing. all ok. No vacuum leaks, No drivability problems, No MIL's. Sometimes, It will be running fine, I will shut it off for a minute, and when I restart it it will idle low. Sometimes, it will go back up to 800rpm sometimes not. I will drive it for a few days with no problem, then it will act up again. Doesn't seem to care if the A/C or any other load is on. Also got this problem with my cruise control. After the first time I turn it on after not using it a while(few days or so) it will shut itself off. Not like hitting the brakes or the cancle switch, Litterly off, like hitting the master switch for cruise. The light on the dash stays on and if I press the set button again it will start back up and never have another problem.

So thats my story, anyone ever had this?

 

Well i can really relate to this. I have a 93 v6 3.0 and I noticed that it was doing exactly the same thing (the idling, not curise control; don't have cruise on mine)

So since it was right after I had cleaned the throttle body that I really paid attention to the idle I thought i may have screwed somthing up, however I did notice it always sorta did it before...

Anyways, so I asked many MANY different people about it. Private mechanics, dealer mechanics... nobody had an answer for me.

So finally I had a chance to speak with the head technician of san francisco toyota. He seemed really knew his stuff...

He gave me a really long detailed explanation which I can't recall now, but to sum it all up; it has to do with vaccum.

When the motor is warm, there is a different amount of vaccum in there and as soon as you gas it a couple of times it inhales more vaccum.. somehow this is all associated with the ECU and it controls how much air flows... bottom line, it is normal.. although 300 does sond a bit low. I don't think it should be going that low. You might have a clogged vaccum line or something. Could also be somethign mechanical, like the dashpot .. maybe it's worn out an keeping the throttle a little too low sometimes.

Also, since cruise is vaccum operated (I think) this might be associated...

good luck!

 

funny you mention. i just asked a similar question about my idle. ididnt mention that it was 3-400 as well. i only got a few responses, maybe more will respond to you. i'm looking for answers as well. - Kyle

 

so how do you clean the vaccum lines then?

 

to clean the vaccum lines.. umm.. i don't konw, however, i was told that since the pcv valve on 93 v6 trucks is made of metal, it is very unlikely that it would fail and instead of replacing it you could spray some throttle body cleaner into the tube and it would go through and clean out all the carbon deposits leaving the valve free to do its job. However, I don't agree that cleaning the valve is sufficient becuase there are moving parts in there that can wear out.. i think there is a spring too which can wear out over time. I would just replace the damn thing.. hehe

but i believe u can spray some throttle body cleaner down there.

dont' take my word for it, wait until someone knowledgeable chimes in to confirm my statement(s).

 

UPDATE:

Thanks for the posts, I decided to reclean the throttle body but this time I took off the three vacuum lines on the top of the intake. I shot some carb0clean through & I ran some compressed air throug to help things along. I also scrubbed out the port on the lower side of the throttle body(insde it) The thing still varies the idle but now it is between 1100 & 700 rpm. I am thinking that it has to be some kind of debris in the system somewhere or maybe a plugged IAC port or something. I think I will go out and pick up osme GM Top Engine Clean (Best carbon disolver around) and you can get it in spray form. I think I'll give that a try & see what happens. I'll post with results ASAP:pat:

 

thanks, i would like to know what happens, Kyle

 

I have heard that you should be carefull when cleaning the throttle body so that the throttle position sensor (TPS) doesn't get any TB cleaner on it. The cleaner can cause the TPS to fail. Here is some info on it
http://4crawler.cruiserpages.com/4x4...l#ThrottleBody Good luck.

 

mt goat, you've gotta be one of the most helpful guys on this site, your always appreciated. Kyle

 

Well thank you my friend. I do try to help, sometimes. How's everything over in Tulsa town?

 

oh its just dandy here in tulsa. hows everything down your way? its a little too warm for me, for fall weather. but i will get out in it tomorrow maybe do some biking. i am really starting to get the mod fever but i must resist! other things are more important i really wanna add some stuff to my truck so i can join some of the local clubs on their runs, but i dont wanna spend the money. any idea on how i can do that? freakin a. take it easy, Kyle

 

Try replacing the oxygen sensor.