How is it possible to adjust idle on a T4R V-6 when vehicle stalls at anything below 1,000 RPM's ?

As soon as I take my foot off the gas, it stalls … every time.

Or, is it stalling for some other reason ?

There is a throttle stop adjustment that someone before you could have messed with.

My high idle on the 97 Puppy Hauler was a dirty IAC.

It could also be a vacuum leak. However, my last vacuum leak only caused the P code for System Too Lean and idled just fine.

To me low idle stalls means you have a cylinder or two not firing at idle. Toyotas missfire detection is poor.

Plus is you just got this back together there may be some adaptives it needs to relearn. Which involves just driving it under normal conditions while it remaps everything. You went from too low of an idle to too high.


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It’s stalling for some reason other than idle speed adjustment.

You’ve been chasing several discrete problems and treating them as individual problems. Alternator issues, oil pressure issues, now stalling issues. You make it sound like these all started suddenly, out of the blue. Have you considered that you have a bigger problem and you are chasing symptoms?

Not trying to be disrespectful but sometimes it’s ok to ask a professional to have a look.

Idle speed cannot be adjusted. Dying at idle usually indicates a clogged or broken IAC valve or a massive vacuum leak.

Might as well to pull the throttle body if it dirty, that way you can give it a good cleaning. and since it's out, make it easier to also pull the IAC and give that a good cleaning. Put is all back together and have the truck relearn idle speed by driving it around and idling.
Do a search on here and it will give you instructions on how to do these.

Check that the air hose hasn't become disconnected from the throttle body.

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I haven't seen your other threads, so don't know what you've done already. But easy, cheap, and good first steps would be to clean the MAF sensor and the throttle body.

Since it was mentioned, here's a video you can use for the testing and cleaning of your IAC valve.

Yes, you are correct. But as far as I can tell, the problems did "start out of the blue". Everything went to hell when the alternator died.
I had just bought the vehicle and I did not drive it, because I did not yet have Mexican auto insurance, I spent time getting it ready to pass a California smog test. I cleaned the MAF, new Denso spark plugs, oil change, new air filter, new battery. Every thing SEEMED to be working fine. Finally got Mexican insurance and I drove it to the U.S. Waited in line for 1 1/2 hours to get across the border (at idle). Got on to the I-5 and it stopped dead. Not even any running lights. Next morning, Auto Zone recharged the battery and they tested and told me that the alternator was bad. They said I'd be able to run on battery power alone, long enough to get back to Mexico.

Got within 2 blocks of home when it died, again. Towed it back to the secure parking lot. Recharged the battery again. Ordered and installed the Amazon alternator. Started it right up and everything SEEMED to be working fine. Idled it until warmed up. THAT IS WHEN IT STALLED. I know next to nothing about auto mechanics but it sounds like I have a problem with a HOT IDLE. ????

NOTE: The only place in Tijuana that MIGHT be able to diagnose the problem(s) is the Toyota dealership. But, God knows how much they would charge for such service. $1,000 USD or more ???? I might easily spend more on repairs than I did on buying it. ???? Every other place would rip me off and THEN still not find the problem.

At this point, as other posters have pointed out, I have little to lose by removing the throttle body and IAC and cleaning them with CRC throttle body cleaner.

Being retired, I have lots of time, not much extra money, and only a small amount of knowledge.

Do yourself a favor and test the IAC ohms resistance too with a multimeter like I show in the video. Also apply 12V power to it and confirm it opens like it should.

Not a bad place to be honestly!. Time to gain the knowledge which prevents wasting money throwing parts at it or someone else diagnosing.

If you don't have it 96-02 FSM. Good read.
Complete 4Runner Service Manual 1996-2002.pdf - Google Drive

japan-parts.eu Type in your VIN or Frame numbers great part number source.
Have also used site drawings for assembly/disassembly visual.

It's all fun Good Luck !!

You say all hell broke loose when the alt died. And now stalling issues. When your rig lost all power and died, the ecu could have defaulted back to the stock parameters, including how to idle. Having your rig parked and idling will help the rig adapt the correct idle.
I think you should still service the throttle body and IAC as part of maintenance.

Right this minute, before I clean the throttle body and the IAC, IT WILL NOT IDLE. IT STALLS EVERY TIME.

PS: Is it true that a trickle charger will NOT completely recharge a 12 volt battery if it is completely dead = reading ZERO VOLTS. ??? (when the alternator went out, it ran on battery power alone until it was completely drained down to zero volts.) NEW BATTERY WITH COMPLETELY CLEANED TERMINALS.

You will never drain a battery down to 0 volts. The truck will stop working LONG before that. You need to get a cheap multimeter to start this testing process. If the battery truly did somehow get down near 0 volts, it is likely time for a new one. The battery should be 12.6+ volts with the truck off and 13.6+ volts (really 14.0+ until warm/hot) when running. Test at the terminals of the battery.

A trickle charger might not be able to bring back a totally discharged battery (what did the indicator lights on the charger tell you?), but a mostly discharged battery would be brought back in a few days.

Cheap replacement alternators (the stuff you can easily get from the auto parts store) are junk. You should put on an OEM or Denso reman unit if you want to be sure that is not your problem.

-Charlie

Draining a battery completely can damage the cells and result in it no longer being able to take and hold a charge. If that happens, it doesn't matter what you use to recharge the battery, it won't work. Some trickle chargers claim to be able to restore batteries that have been fully drained and damaged, but not completely killed, but I've never tried that myself so I can't speak to whether that actually works. I suspect it will depend on the battery chemistry, and how badly damaged the cells are.