My wife's 1999 SR5 4x4 (5VZ-FE 3.4 L) has been idling low since we bought it last year (about 8 months). I rarely drive it, so I was a little surprised to find it had gotten a little worse since the last time I was in there. When the engine's warmed up and you're stopped, the engine idles at around 500-600 RPM - it sounds like it's thinking about cutting off if this gets much worse.

I've also got a hoover/vacuum like 'hoooooooo' sound when I'm giving it gas to accelerate - don't know if that's the same problem or what.

I just got finished cleaning the throttle body and MAF per THIS WRITEUP. I've also taken a look at the vacuum hoses, and replaced one or two that looked about ready for a change-out. Neither did much for the problem, though I noticed a slightly smoother running engine after doing the maintenance.

Can anyone suggest what I should tackle next?

EDITED TO ADD: Discovered that the idling issue doesn't affect park or neutral gears (see third post in thread), just drive, reverse, etc.

 

Search of for IAC. Idle Air Control valve. Most likely your problem. They are prone to get gummed up, and need a cleaning every few years. Here is a link:

https://www.yotatech.com/forums/f123...ac-pics-92286/

 

Okay, I just got back in from pulling the throttle body (TB) and cleaning the Idle Air Control (IAC) Valve. I basically followed the procedure described in THIS THREAD. Dittos, BTW, for the use of an impact driver to remove the 4 screws connecting the IAC valve to the TB - they were on very tight and would have stripped for sure. I stopped work and went out to buy an impact driver from O'Reilly Auto Parts (Sears didn't carry one), and I'm glad I spent the $12. I forgot to pick up a tube of sealant, so I didn't reseal the two screws mentioned in the article, but I'm going to go back and do that.


UNFORTUNATELY, I'm still experiencing the low idle problem on the 4runner. I just noticed that the idle issue depends on my gear. It's still idling low (550-600 RPM) in any gear except N or P. In Park or Neutral, the idle goes up to 700, within specs. Within specs idle speed for the 3.4L V6 engine is 650-750.

I'm up for suggestions - I'm not sure where to go from here.

 

Still hoping for a suggestion on what to do next...

 

Did the Hoover vacuum sound disappear?

 

One thing you might do is put some really potent fuel injector cleaner in it and check all your filters. Oil, Fuel, Air etc. I know the oil filter has nothing to do with that but check it anyway. I had an old Ford that did that once (I know it is not a Toyota) and it actually needed a new fuel filter because when in gear it was not getting enough fuel to the engine. Diesel engines and gas engines both have the problem even though a diesel does not have the same filter but anyway. I would check all filters. And clean fuel injectors. That vaccum noise can actually be the fan, there is a bushing in the center of the fan that goes out and sometimes it will break and the fan will spin extremely fast and make that noise. It does not help that you do not run it alot though, because every vehicle needs to be at least started every now and then to keep it from dying on you.

 

rimpainter.com: nope, still hoovering.

future_sailor100: The air and oil filters have been replaced several times. Might be a good idea with the fuel filter...air+fuel+spark and from everything I can tell the air's ok and I'm about to change out the plugs.

Don't know where you got that we don't run the truck a lot - we drive it just about every day.

 

Yeah sorry about that I was thinking about something else while I was typing I am currently working on another persons truck that never starts and I got my thoughts messed up. But definately check the fuel filter, and one thing you can do to check air is take the air filter out, start it, run for about 5 seconds, replace filter, start again. And sorry again for the mix up.

 

Ok what plugs are you running??? if you are running 2 step cooler this effect may occur so that is a possibility. and the temp sensor is another possible culprit. as well the maf may need cleaned, if it is dirty it will sense less air intake and can cause this situation......

 

One thing you might do is put some really potent fuel injector cleaner in it and check all your filters. Oil, Fuel, Air etc.

is still a really good idea!!!!!

 

I suspect these are the original factory plugs. I haven't pulled them yet. I just ordered some denso plugs. I cleaned the MAF the other day. It's a stock 1999 SR5 4x4 with 160k miles on it


So, would adding seafoam to the gas tank be a good idea?



Things I've done to date:
* Changed oil and filter
* Replaced air filter (well, back in Sept., but the problem dates before and after the change - filter still looks pretty clean)
* Removed and thoroughly cleaned Throttle Body
* Cleaned MAF
* Cleaned TPS
* Cleaned IAC Valve
* Checked vacuum hoses and replaced several with cracks



Next up:
Plugs
Probably fuel filter

 

Checked vacuum hoses and replaced several with cracks
Keep going with the rest maybe one you have not found!!!!

Seafoam in the tank is a good Idea just not the block unless you have done this regularly, and run some through the intake on the vacuum line.

The plugs should be replaced definitely !!!!!!!!
the reason I mentioned the plugs in the first place is my truck idles about the same with the 2 steps cooler plugs I use but I like since it is a standard.

other than that the Temperature sensor may need replaced...

 

Just a shot in the dark, but make sure your plugs are dual electrode. I would say more often than not they try and sell me the single ground electrode plugs, and I have to tell them to get me the dual. Even Toyota has sold me the wrong ones.

 

Can you post a soundclip or vid of the "Hoover sound" you're talking about? I'm concerned it's related to an exhaust leak, pre bank1/2 02 sensor(s).

 

what kind of air filter do you have installed in this truck!!!!

 

rimpainter.com: I'll try and record the sound later this week, if I can.

eddieleephd: I think it's a fram air filter (ducking the shoes thrown at me). Could that be responsible for the sound? It's approaching time to replace it.

 

the reason I asked is I am running a K&N OEM replacement filter and I get a similar hoover sucking sound when I get on it! so I do not know about the FRAM filter since I have never run one in my truck... Definitely record the sound so we may hear it and get a better idea of what you are hearing... another Question is do you have a deckplate mod on this air box??? or the Drilled out holes in the bottom??? any modifications to the air box, and have you replaced any more of the vacuum lines?? and can you say which lines you have replaced like the PCV vacuum line???

As well be sure to check the intake for cracks and such this could cause the hoover sound and the idle issue!

 

also check this link out if you have not already
http://www.mr2.com/files/mr2/techinf...a/3vzVS5vz.pdf

 

Got outside and changed my plugs out today. I discovered that the plugs in the engine from when we bought it were NGK BK5RE single electrode plugs. I hoped that was my problem, but despite changing them out to Denso K16TR11 dual electrode plugs, the idling problem is still there.

The plugs on the passenger side bank seemed to have a little more carbon deposits than the driver's side ones. Passenger side plugs also had a pink hue to the ceramic on the center electrode, while the driver's side ones were bone white. Is that a clue? Picture shows passenger side plug (left) and driver side plug (right).




I discovered another possible issue while I had the intake off. I was holding the intake silencer (the plastic box between the air cleaner and the throttle body - see photo here). Abruptly, I noticed that I was dripping motor oil all over the floor! I ended up collecting a good 1/4 to 1/2 cup of motor oil out of the bloody thing, from where it had collected in the 'box' part. There is a slot inside the tube part, and that's where the oil was coming out of. I've no idea where it came from, but it was a fair bit of oil. What's up with that - it can't be normal, can it?



I also added a full can of SeaFoam to the gas tank the other day and topped off with premium (I typically run regular unleaded). I was hoping to possibly clean up any fuel injector gunk with the SeaFoam, but I haven't noticed much effect.

 

what about wires?? and the oil would prefer a pic to know more!