CUBERA

I looked up a search on this problem but found too many opinions, hopefully you fellas can help.

My 98 runner stalls occasionally with the a/c on mainly.
But with a/c off it does not stall.

My idle with air on is 600rpm.

Today while letting off my gas pedal at 25mph for 3 seconds it stalled but then quickly restarted.

Then while sitting idle in drive mode for 10minutes to pick up my daughter at school it stalled. This story has occured 3 times at her school.

My fuel filter was changed 9months ago, along with new timing belt and plugs at the dealer before purchase. I cleaned throttle body with "o" gasket mod. 3 months ago.

I'm wondering if the oil from amsoil filter is getting on maf sensor?

Mad Chemist

I'd try cleaning the MAF with a spray can of CFC sensitive electronics cleaner. 600 RPM seems a tinge on the low side (I think~700 or so is normal?). Try a bottle of fuel injector cleaner as well. When you cleaned your throttle body, did you see any oil residue on the indside? Would be evidence of over-oiling your air filter. You could also try a cheap paper filter for a little while and see if that makes any difference. Possibly an O2 sensor starting to give out? Replace your PVC valve as well if it hasn't been done. Just throwing out some suggestions....

MTL_4runner

I would try cleaning the MAF also and do try a paper filter just to be sure that is not the trouble (doubt it tho). Also change the spark plugs (use OEM Densos at stock gap) and check again to ensure the throttle body is free of all carbon buildup. Finally put in some Techtron injector cleaner to clean out the fuel system.

CUBERA

I just did all of the above cleaning entire intake, tb, maf, techron fuel treat. I got the amsoil filter 4 months ago. Do i re-oil already? Have not done the O2 sensor. It seems to be idling better now at 600 with air off and 700 with air on.

Where is it and how do you go about changing the 02 sensor?
Do you get it at the dealer or auto store. I got the PCV valve at autozone.

Mad Chemist

Hmmm, O2 sensors aren't cheap, I wait and see if what you've done does the trick. You shouldn't need to re-oil the filter unless you've been driving through a ton of dusty conditions, but I've only run K&N filters before, so I'm not sure about the Amsoil

lunatic14r

stay away from your daughters school and it won't stall

I would check the idle air control motor you can remove it and clean it they get corbon on the valve and stick.
does it shutter or shake just before it stalls ???

CUBERA

Thanx for all the replies fellas. It actually does shake and shutter a bit then stall. Where is that air control motor located and what chemical do i clean it with?
No doubt, i just called autozone and they said 147 bucks for the 02sensor. Yikes!

Is there a way to check those bugers?

lunatic14r

clean it with a good carbon cleaner (berkabal 2+2) and let it soak for 20 min you may have to scrap it a little. the IAC valve it on the upper intake it will have a a connecter on it (i think a 3 wire not sure) its behind the throttle plate

MTL_4runner

It is the green part right under the trhottle body:


Make sure you clean it really well before putting it back together.
I very much doubt it is the O2 sensor.

BruceTS

I doubt if the MAF is causing the problem, I'll have to look up exactly what systems are activated when you turn on your AC to give a more exact answer, but usually when the AC switch is turned on, it kicks in another circuit to control Idle. Also there is a vaccum assy on the throttle body that controls the rate which the Idle drops at, when you let off the gas.

Check your vaccum lines to see if any came off or are cracked, an air leak can cause erratic idle too...

MTL_4runner

Anyone know if there is an EGR valve on a 3rd gen?
If so do you have a pic?

EGR's can cause this too but I am not sure there is one on this year truck.

CUBERA

Can i use carburator cleaner on this?

lunatic14r

yes carb cleaner will work fine but soak it in the carb clean for 20 min or longer let us know how you make out. IAm about 90% posative this will fix your problem if it was something else (egr valve) it would turn on the check engine light

CUBERA

Thanx a bunch everybody and lunatic.

Have never seen a check light.

Rock on forum.

I'm goin for the carb clean of the idle control valve to see if this improves it even more than the whole intake and fuel treat clean job.

MTL_4runner

Good old carb cleaner will work fine.
Let us know how you make out.

lunatic14r

no problem GM dealers sell this awsome stuff called top engine cleaner and it will clean ever last bit of corbon from you top end fuel adatives only do some much the top engine cleaner wont really get it to the small pasages like you IAC cirkit but it will cure rough idle problems and will restore some power back caused from restricted air ways you might to but some of this through the top end after you fix the problem so this problem wont happen agian

MTL_4runner

I used to pour that stuff in when I take the intake off.
Works great to clean off all the valves......great stuff!!!

lunatic14r

yea it works awsome I pull off a vacuum hose and let the engine suck it it but you have to be very very careful not to suck to much at one time cuz you can hydro lock the engine

MTL_4runner

I used to pour a bit into each of the intake valves with the intake off.
Let it sit overnight and then reassemble in the morning and fire it up.
All kinds of crap comes out but it usually runs like a champ after...never hydrolocked it tho.

CUBERA

Got done a while ago and took out the entire tb, then took apart the idle control valve unit.

It was gummed up pretty bad, so i soaked it and brushed it clean as a whistle along with my whole throttle body.

Results seem better only time will tell. But my rpms while in park and up to normal operating temp. is 850 steady with air on.

With the air off my rpm's are fluctuating every 10 seconds from 600 to 700rpms back and forth. Is this normal?

I also been noticing lately a slight loose belt or pulley noise but i know my belt's look good and tight.

I had timing belt replaced at the dealer when i bought it along with new plugs.

Any ideas?