2001 low idle problem

J

jiminton40

New member
Hey.. new to the threads and it looks like a life saver. I have an 01 and when the automatic tranny is in drive and idling it is awful low. The truck has always idled a little low (as I have noticed out of many 4runner owners) but mine is starting to rattle the dash and work its way up and down the rpm gauge. I haven't tried spark plug and wire replacement and there is no check engine light (so I am ruling out the o2 sensor). A little in the dark here, so any suggestions would be helpful. Thanks.
 
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The normal idle range is 700 ±50 iirc. I would start with a clean air filter (no more than 15k miles on it for paper type) and a clean MAF sensor. You can find threads on cleaning the MAF sensor here and most auto parts stores will carry a Mass Air Flow Cleaner spray. Most would recommend a clean throttle body and idle air control after that. Welcome to the site!
 
Idle range for now is just above 800. Like I said, it has always been that way but recently it has dropped when idling in drive. Neutral and park perks the range +50 or so and purrs like a new one. I will give the air filter a shot and see if that works, and just in case, would the MAF sensor show up in the form of the check engine light? I'm not too familiar the MAF, and if it gets to that, I may have to get some help on locating it. Thanks for the help. If this works, it will save me some cash and time. Appreciate it.
 
Your #s are normal, ~750 in P (warmed up) and ~650-700 in D. When cold it should idle ~1400 and slowly work it's way down over ~5 minutes. It shouldn't be shaking though, are you sure it's not missing?
 
Pretty certain it's not missing. It almost seems like the idle is up and down enough to cause a rattle in the cab but not enough to show much on the gauges. I know that sounds crazy, but there are no thuds or hitches in the idle like something is slipping. It's really not a big deal to most, but I just don't want it leading to more problems. My plan now (after some research) is to change the plugs, wires if necessary, and replace the air filter. After the first response to my post I went and checked the filter and it looked a little dingy. I pulled it away from the casing just to let some fresh in and noticed no difference but replacing it can't hurt. When I get some time I will check to see if one or more of the plugs is fouled. It has 160k on it but it is a machine, like most that have been taken care of.
 
Be sure to clean the the throttle body and IAC (idle air control) like 004Gunner mentioned too. You may want to test the voltage/resistance on the TPS (throttle position sensor) also to make sure it's within spec.
 
Uh oh, now you guys are talking some stuff that's a little over my head. Learning as we go, and I want to figure this out. I'm new to some of the advanced stuff, so patience for the ignorant would be appreciated haha. I'll be sure to clean the throttle body, but how would I go about testing the specs on the TPS?
 
Last edited:
Same Problem on 2001 4Runner 3.4 2WD

I also have a low idle (500 RPM in drive) and a slight shake when stopped at a light for example. I don't think it is missing because when I raise the idle with a slight pressure on the gas pedal to 700 RPM or so, it smooths out nicely.
After cleaning the TB, (the filter is new), same problem.

My question: is there an idle adjustment screw or other idle adjustment control or is this handled by the ECU exclusively?

Also just a quick word about this forum: it's great! (well, I guess that was 2 words...sorry).

Thanks in advance,

ZZ
 
brian2sun said:
Your #s are normal, ~750 in P (warmed up) and ~650-700 in D. When cold it should idle ~1400 and slowly work it's way down over ~5 minutes. It shouldn't be shaking though, are you sure it's not missing?
Click to expand...

Mine has been just the opposite since I did my valve covers, when I start up the idle is around 5 to 600 and when it's warmed up at a stop the idle is right around 1500. Going to clean my MAF this weekend and possibly the throttle body too. Any other ideas or should this take care of it.

Thanks

Gary
 
Same low idle issue

Hey everyone,

Gonna bring this one back from the dead... I'm new to the forum, glad I found it. Our 2000 2wd SR5 is our work horse and DD. I'm having the same low idle as some of the members have stated here. Sometimes it starts up fine and idles normal... 700 or so... but sometimes it fires up and almost dies... falling to an idle of about 350. It will almost stall with the accessories pulling on it at very low speeds under no throttle, etc. power steering.

I've begun checking all of the vac hoses around the intake manifold. some are old and crusty, need replacing, though playing with tthem didn't seem to raise the idle at all. If I pull one, then engine will die in seconds.

cleaned the MAF....

gonna do the plugs tonight...

otherwise I've got nothing but question marks...

Vehicle drives seemingly normal.

Dave Funston
 
Ape-X said:
Hey everyone,

Gonna bring this one back from the dead... I'm new to the forum, glad I found it. Our 2000 2wd SR5 is our work horse and DD. I'm having the same low idle as some of the members have stated here. Sometimes it starts up fine and idles normal... 700 or so... but sometimes it fires up and almost dies... falling to an idle of about 350. It will almost stall with the accessories pulling on it at very low speeds under no throttle, etc. power steering.

I've begun checking all of the vac hoses around the intake manifold. some are old and crusty, need replacing, though playing with tthem didn't seem to raise the idle at all. If I pull one, then engine will die in seconds.

cleaned the MAF....

gonna do the plugs tonight...

otherwise I've got nothing but question marks...

Vehicle drives seemingly normal.

Dave Funston
Click to expand...

Hi dave, welcome to t4r.

So under some cold starts it sputters and takes giving the accelerator some go to get to normal idle right? Check out the IAC valve, there is usually carbon buildup. Clean that out and the throttle body with some carb cleaner

http://www.toyota-4runner.org/3rd-g...ottle-body-adjustment-including-iac-pics.html
 
blizz86 said:
Hi dave, welcome to t4r.

So under some cold starts it sputters and takes giving the accelerator some go to get to normal idle right? Check out the IAC valve, there is usually carbon buildup. Clean that out and the throttle body with some carb cleaner

http://www.toyota-4runner.org/3rd-g...ottle-body-adjustment-including-iac-pics.html
Click to expand...

So the starting good idle or bad idle didn't seem to be dependent on outside temp. Mornings it would usually start fine, but when I'd go to the car at lunch then it would have the problem. HOWEVER!

Lastnight I pulled the TB and IACV, did some extensive spraying and cleaning with MAF and TB cleaner, and then reinstalled. There was a LOT of black buildup (I'm guessing oil? carbon?) on the little valve gate and on the TB side of the channel. Got the valve sliding smoothly, though I couldn't remove all of the buildup. Would probably need a stronger cleaner or some better hand cleaning tools, small wire brush, etc.

The car then fired up strongly and settled down to a really smooth 600rpm at op. temp. Fired up great this morning too so I'm hoping this was the ticket!

I also pulled the plugs, they didn't look too bad, but I'm going to replace them next chance I get anyway as its been over 3 years or so.

So Blizz86 as you recommended, cleaning the IACV seemed to be the solution for me. Its frustrating reading a lot of the other posts like this and seeing people clean EVERYTHING under the hood and still having issues. Lots more under my hood to replace, cracked and old VAC hoses, etc... but this will hopefully keep the truck reliable for a little while longer!

Glad to be on the forum.. .looking forward to fixing up our baby.

Dave
 
I need help with my 99 sr5 please !!!!

So I've been doing research and searching.... I'm new to the forum but been using info on here for years!!!

I have a 99 sr5 2wd 3.4
Plugs, wires, o2 sensor replaced 20k miles ago...

I've been having symptoms of s bad IAC (rough starts and having to hold down gas o keep idle up in the morning) so with all the research I ended up replacing it with a aftermarket iac and new gasket. At the same time I cleaned the throttle body and MAF. Disconnected the battery to reset.

Problem is worse!!!!

Now idles at 500 rpm with same same symptoms (not just cold starts). Now when I initially turn the AC on toms boggle from 450-500 for a few seconds. Checked for vacuum leaks.... Not sure what to do next

Other than that the runner accelerates and runs way smoother when driving. Problem is only when in idle and starting.
 
Anyone ever find a solution to this issue? I'm having the same issue on my 99 4runner with 217k. So far we have changed the following:

IACV
MAF sensor
Cleaned throttle body
Fuel Filter
crankshaft pos sensor
camshaft pos sensor
spark plugs/wires

NOTHING has changed. Truck is fine when it's not at temp yet.. but when it gets to temp it starts idling rough intermittently at red lights when sitting too long, and eventually RPMs dip down to 4-500 and it stalls.. Starts right back up no problem though. I'm at a loss and I'm tired of throwing money into it. Any help?? Will clogged cats cause this problem? That will be the next thing we check.
 
My '06 Avalon - 2GR-FE engine - threw a MAF code about 6 months ago. P017x - forget whether x was 1 or 2 - it translated into "rich". One of the trailing numbers is lean; the other rich. I pulled the MAF and cleaned with the CRC product, let air dry; then reinstalled. Erased code before starting. CHECK light gone. MAF sensors do wear out.
 
christina818 said:
Anyone ever find a solution to this issue? I'm having the same issue on my 99 4runner with 217k. So far we have changed the following:

IACV
MAF sensor
Cleaned throttle body
Fuel Filter
crankshaft pos sensor
camshaft pos sensor
spark plugs/wires

NOTHING has changed. Truck is fine when it's not at temp yet.. but when it gets to temp it starts idling rough intermittently at red lights when sitting too long, and eventually RPMs dip down to 4-500 and it stalls.. Starts right back up no problem though. I'm at a loss and I'm tired of throwing money into it. Any help?? Will clogged cats cause this problem? That will be the next thing we check.
Click to expand...

I'm not a mechanic but I can relate a previous experience for your thoughts...
I've had a vehicle that had low engine idle problems. I even went as far as to remove the air intake so far as to where I could watch the butterfly in my throttle body. I noticed that when the engine stalled, the butterfly would completely close. When the engine was running, the engine vacuum would pull it open slightly. If I pushed the butterfly open slightly, the engine speed would increase. I didn't notice any resistive force due to an actuator trying to do something against what I was "testing". Then I did something that in my eyes was totally reversible. I drilled a 1/8" diameter hole in my butterfly. It brought up my idle speed. I liked the result so I tried to drill a 2nd hole to kick up the idle a little bit more. After a while I threw a code for "high idle speed". I simply installed one 1/8" pop rivet into the butterfly and that's how I run her.

Granted, I did this only after doing all the basic items discussed in this thread with no noticeable change after my efforts. Increasing the airflow, although only slightly made the difference in my vehicle.

YMMV
 
Sorry for replying to such an old thread.
I have a 2000 Limited, so it has the 3.4. Automatic transmission.
Recently it started idling at a tad under 500rpm, which I immediately noticed because it used to idle at around 750rpm. There’s a light vibration, the gas pedal is unpredictable, there is major rollback on hills, and it doesnt roll forward unless I press the accelerator. I believe this is all due to the low idle. How do i fix this? There’s no check engine light either, and once the car is moving it drives great.
 
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