Greetings all!

2000 4runner, SR5, 4x4 and somewhere around 350K miles.
Hope I can get a little help with an annoying problem regarding occasionally stalling while idle.

I have been using my 4runner as a work vehicle and it require a good bit of idling between short drives. The first many days it was fine, but then I noticed that RPM's would occasionally dip below the normal 700rpm (+/- 50) and sound a bit erratic. When getting low enough, perhaps 250rmp, it would surge up higher than normal, settle for a short bit and the idle would hunt a little before repeating. Sometimes it would not recover and die. It starts up fine both cold and warm and after it has died with the idle problem.

Here is what I have done:
Added injector/throttle body cleaner to a tank of gas. Sucked a can of Seafoam through a vacuum line. Cleaned IAC which had some build up. Cleaned throttle body, which actually didn't look bad at all. Replaced MA sensor. Replaced plugs, wires and new coil pack's. New air filter. Filled up from three different brand of gas, and from a multitude of gas stations.

When I first got this ride, about 3 years ago, I did notice the idle issue a couple of times after it died after prolonged idle, but not really since until just recently.

Bonus question:
There are two small "pipes" on top of the throttle body, both bend 90 degrees towards the rear. Both are blocked off with some small tubing/hose. I assume they should have some thin tubing connected to who knows where. What are they and should they be connected? It has run fine as is for almost 100K miles.

Thank you!

Claus

 

Some of the VAC ports on top are suppose to be plugged, you can double check that with the vacuum routing info under the hood I believe. I'm thinking vacuum leak from somewhere(test using propane or carb cleaner), intake tube, PCV, Vacuum lines, intake manifold, crack in plastic EVAP tank, Throttle body shaft o-rings, check the TPS range and for consistency(starts off at 10% throttle) it should be smooth with no blips or drop outs, tighten throttle cable up, and perform these checks on the throttle control motor and TPS in the link below, check the Coolant temp sensor ECT for the ECU to see if it is within range(if it thinks your cold it will flood it). Check battery connections, engine grounds and voltage at different RPMS insuring you see 14V around 2000RPM, could also test battery AMP output . I assuming you have all the correct dual ground plugs, decent wires and good connections at the coils. You can scan through the FSM and perform other suspects aswell.

TPS check
http://www.teamtoyota4x4.org/archivi...thrbod/ovi.pdf
ECT check
http://www.teamtoyota4x4.org/archivi.../ects/insp.pdf

On a side note from your post in TR4 the PO probably replaced the fuel inclinometer behind the dash due to a TSB for incorrect fuel level which would reset the odometer if the dealer doesn't take the time to pre-set the odometer properly which isn't included in the TSB instructions and therefor never done, the dealer should have documented the exact milage before the TSB was performed and had the owner sign off on the change. info overload - This should have been a Recall, running out of fuel on the hwy loosing power steering and power brakes is dangerous, also running out of fuel in the middle of nowhere could be lethal, my concerns fell on deaf ears and I paid 800 to replace the known defective parts that rolled off the assembly line.

 

That was a wealth of info and checks, and I'll go through them one by one.
I did tighten the throttle cable a bit already.

The temp reading is from the OBD port, so I'll assume that is what the ECU see as well.
What I may have failed to mention is that it idles fine 9 out of 10 times, but prolonged idling will eventually make the RPM's dip slowly, and sometimes it catches it and throttle up and a few times it just dies.
some of the vacuum hoses doesn't look too good and the one connecting to the TB has a rip in it where it seats on the pipe, so that is the first step, along with a new PCV valve.
When I replaced plugs and wires I noticed that one of the coils had almost no post left and filled up with a bunch of black powder like crud in the bottom. Another coil didn't look so good either, so that was why I replaced all the coils.

On a positive note it does seem peppier, especially at mid range (around 2500 RPM), and driveability has never been in question ad long as I have owned it.

Thanks again!

 

Yes the ECT on the front of the engine sends info to the ECU, should be around 190-200*, the one on the rear is just for your gauge. You may wanna replace the IAC/throttle control motor since this is only happening during idle randomly, if its intermittent it may check out fine but flake out under normal operating conditions. If you tap the throttle when it does this and it stays running, it would be an indication the IAC is not functioning properly. Careful with the grommet for the PCV valve if you decide to replace it, it will likely crumble and it might be wise to remove the VC to avoid debris falling into the topend.

Report back your findings.