thefreqofnature

The title just about says it all. I have an 88 3.0 5 speed 4Runner. It starts ok and warms up and after a few minutes the idle drops to where it should be maybe 850 rpm or so. Then after driving it I'll stop somewhere and shut it off for a while. Then when I start it up again it will idle at about 500 or less. Any ideas?...need more info?...let me know. Thanks everyone!

keithguts

Check all the vacume lines is the 1st thing to do.

itsmeagain5789

adjust idle screw. i had to do mine last month. its fine now.

thefreqofnature

I don't think I explained my problem very well...sorry for the confusion. There are times when it idles perfectly at 850 or so. Like after start up in the morning. Then sometimes, seamingly for no reason it will idle at around 500. Like after a short stop. Typical situation. I'll start the car in the morning...it will idle at around 1700rmp until after a couple of minutes it will warm up and the idle will drop to 850 where I've been told it should be. I'll drive it for a few minutes, a few miles, and stop to get gas or to get coffee or some other reason. Then when I go to start it again, it will start fine but will idle around 500. Hope that explains it better

UKMyers

Mine does that sometimes but not very often. I'd pull the intake tube and clean the throttle body out real well before jacking with the idle screw. At dirty TB has been known to cause idle issues.

pruney81

Yea mine does that once in while too, it did today as a matter of fact but it ususally idles fine

itsmeagain5789

o yea, if u havent cleaned the throttle body, clean it. also, check all your wires going to the distributor. one of mine was loose, so every time i hit a bump, it would try to cut off. but yea, i finally mesed with the idle screw a little bit when it was doing the problem. it would idle around 300rpm sometimes, only when warm. i've had no problems with idle ever since.

91ToyTrck

would some of these same fixes be the cause of high idle start and fluxing idle upon startup? my truck is fine after a couple minutes of driving, but startup idle is around 2500rpms.

Crymson

Taken to a certain extent yes. The fluxing idle is due to the low amount of vacuum available at high idle speeds 1200+. The startup idle of 2500 is astronomical as well. What does your rig idle at when warm?

Bumpin' Yota

yeah 2500rpm when warming up is WAY too high! ive never seen mine over 1600 ever...

chimmike

I have this issue as well. I've tried adjusting the idle screw, and it does absolutely nothing, whatsoever.......

thefreqofnature

Thanks everyone. Any other ideas?!? My TB is clean, ignition wires in good shape, vacume lines all good as well. My idle in the morning when cold is 1800rpm or more I've aways thought that was high. Any 3.0 experts out there? Thanks again!

TNRabbit

1800 is not bad for cold idle. You can adjust both cold & hot idle. See pic:


Something else to think about; if you are running a thumpty-thump amp(s), the stress on the alternator will pull the idle down sometimes, especially if you don't have a capacitor.

RustRunner89

Was a solution for this ever found? I'm having the exact same problem on my 1989 SR5 manual trans 4runner. Cold start rpm around 1600, when it warms up it's around 800. After driving a little ways, maybe 20 minutes, (temp gauge reads just below horizontal) coming to a stop can put me at 500 rpms, as will stopping and restarting the engine. Checking the FSM for "Poor Idle," there's an option for "low idle" and another option for "incorrect 1st idle," could my 800 rpm idle be considered this "1st idle" since it seems to want to come down a lot after it's been significantly warmed up?

Low Idle Checklist: Engine Coolant Temp Sensor Circuit> Idle Speed Control Valve> EGR System> VAFM> Injectors> ECM
Incorrect 1st Idle Checklist: Accelerator Pedal Link> Dashpot> Engine Coolant Temp Sensor Circuit> Throttle Opener> Idle Speed Control Valve> ECM

I haven't gone all the way through these checklists yet because I'm pretty bad with electrical circuits and my particular version of the FSM is missing all those pages. I'm hoping someone can point me in a more precise direction since this seems to be a rather common problem.

My throttle body is clean, air intake plenum is clean, new o-ring on my idle adjust screw.

RustRunner89

necromancy bump

Rick Booth

I'm going thru the exact same thing right now after fixing a Code 22 (Temp sensor). '91 3.0 5 speed. Morning idle start up 1300/1500-ish, warm idle while driving 1150 but after she's hot idle will drop to 500 or less. However on the highway at speed she's running perfectly again now after also installing a new fuel filter, air filter and in-tank fuel pump. But while screwing around with things a couple weeks ago after getting stuck in the hills over night in Baja, I did mess with the dash pot stop screw and the idle adjustment screw-----so I'm gonna reset those properly today and then clean the throttle body and hopefully get my idle back down to 750-800-ish once again. Will let you know later how I did......

Killemall

I had a similar issue. Not sure if the cure is the same, but mine went away after I adjusted the TPS dead on FSM specs.

gte175x

Bump this thread - I'm having the same exact problem....Low Idle when hot...I just had my timing belt replaced, but I also put some fuel additive in, which it didn't like....I thought it was that, but now that I've been through a fresh tank, I'm not so sure.....and the fact that others have seen the same exact problem makes me think this is.

I know my idle adjustment screw has been adjusted before for too high of an idle, but now that my timing belt has been replaced....is it possible that it's too low? but it's somewhat intermittent too, so it doesn't seem like that would be the case.

To Recap -
1. Timing belt was replaced, fuel stabilizer added --> problem was observed
2. Problem is low idle when hot < 500 RIP'ems and is somewhat intermittent, but is occurring more frequently
3. Driving is no problem, smooth - no issues, only idle

Andrew Parker

About a month ago my sons 3VZE with 240K was idling below 860 RPM so we backed the air screw out quite a lot to bring up the engine speed. This weekend we were preparing to do the valve covers and had pulled the throttle body off. It was very dirty and had a lot of muck in the bore. Then upon inspection of the air intake rubber pipe I discovered a large amount of brown sludge that was in the pleats opposite the breather pipe that attaches to the valve cover. PVC is probably clogged too. When the throttle plate is closed but clean you can see a glint of light all the way around it. As it was it was completely sealed with muck. The warm start bypass air way is in the lower part of the bore and gets fouled with muck too so we cleaned out with B12 chemtool and the idle air screw was carbon fouled as well. We had replaced the o-ring and cleaned this but only a short while ago too. So the engine is definitly tired and this is the result, rapid carbon fouling of the TB and ports. Wth it cleaned up it idles perfectly when warmed up, with approximately two turns out from fully seated on the air screw. Be sure the water tubes are clear in the TB and that you can blow air through the fittings as this is were the heat comes from to make the warm start valve close-off to bring the idle back to 860 after it has some heat load in the coolant and the temp gauge had come up to mid way.

its_ru

So I just had my timing belt and water pump replaced on my 1994 4Runner at 96,000 miles.
my car starts fine when cold in the morning. Idles fine while driving or on the highway. But almost every time I go get coffee or make a stop that is 15-30-40 mins and get back in to start the truck , I feel I misfire and get a low idle, giving it gas helps it get back on track.

I’ve adjust the idle screw, and raising the idle does somewhat help but it makes the truck idle high at park.

I also replaced the throttle position sensor as well and nothing. My throttle body doesn’t look that dirty I went and removed the elbow to check, and I HAVE NOT TRIED ADJUSTING IDLE CONTROL VALVE. But before I go and try to service my throttle body, I ask here do you guys not think it’s a Timing thing?
because the truck cuts on right. And yes it has that occasional low idle start but it’s because it starts and idles fine for 80% of the time I think I’m missing firing and my timing is off.

if someone can guide me the right direction that would be super cool. A timing lights like $20 bucks and little Jumper cables like $5 I already have some tools and can go get more need be.