Joe R

Hey guys,

Having a tough problem here. 2000 Toyota 4runner 5 speed lightly driven for the first 5 years, I bought it with 23K miles, now has 31K. Runs great, except for one thing: when engine warms, idle stays around 1100. Only happens after engine has run at normal temp for a while. The other interesting thing I have noticed is that when warm and I am coming to a stop, say at a stop sign, I push the clutch in just before coming to a complete stop, but the idle will not drop to normal range, it will hang at 1500, then drop to 1100 after the car stops rolling.

Here is what I have had done:

30K tune: plugs, wires, fuel and air filter, timing belt and water pump.

replaced the IAC

replaced the CTS

Checked and cleaned the Aux Air valve (some corrosion there due to a coolant leak).

The first question is should I even do anything more? So it stays at 1100 when hot, is that a major problem? My mechanic said he believes the 5speeds were set up this way so that the RPMs wouldn't come down too much when letting out the clutch on a warm engine (I don't buy it). It is probably using a bit more gas than it should, but I don?t think it could be that much.

Anyway, mechanic said he didn't see any indication that either the TPS or dashpot needed replacing, and that "it is running perfect, according to all the factory settings." No error codes have been showing. He also said that the next step was to replace the throttle body, instead of continuing to guess at what might be wrong (no error codes). One other interesting thing: the car went through 2 o2 sensors in one year (former owner got it fixed--got the records from the Toyota dealer). When that happened, the car had just over 20 k miles on it and was about 5 years old. Given the mileage on the car, I might be willing to replace the throttle body, but I have a sneaking suspicion that may not be the problem.

BajaRunner

Wow it looks like you've really covered your ground on this one.

It definetly seems like a IAC / Throttle body problem. But, I am no real mechanic.

Since you didn't mention it, try cleaning the MAF (Mass Airflow Sensor) that is located right behind the air filter. You can just clean it with electrical parts cleaner. Usually people will throw CEL's if it is bad however.

I had this problem recently with my 100k 4runner. Mine would stall during warm starts, and have 600-800 rpm at stoplights. (Yep, barley stayed running). I cleaned the IAC with carb cleaner and now it fires up like it should.

Other ideas include checking the fuel sending unit and filter.

I for one, would try cleaning the TB very well before buying a new one. And, I have never heard of a TB needing replacement in a late model Toyota before.

Joe R

Thanks SC4,

Yeah, I also think is is pretty unusual to replace the throttle body on a 4runner with this many miles on it. Given the low miles, I almost want to do the tps and dashpot to eliminate them as source of problem, but I don't think that is the smart thing to do just now and mechanic is pretty sure they are not the culprit (he thinks I'm nuts anyway -- says the car is perfect).

How hard/easy is it to replace the MAF? Is it inside the housing for the air filter, or just outside it?

I'll take a look today.

Joe

BajaRunner

The MAF is easy to take out. Its located inline with the tube that connects the air box with your TB. If you do a search on the tech section (I think its in there), you should be able to find some pictures of what you are looking for.

You'll want to give it a good spraying with electrical parts cleaner, let dry for a while, then reinstall.

hross14

Check for vacumn leaks. Grab a can of TB cleaner and lightly spray where intake parts meet. Also check all vacumn hoses for leaks/cracks/holes.

Just an idea but you could also check out the little seleniod (spell check) valves that control the EVAP/Emmissions system and see if they are opening/closing when they should be.

I would try these things first before i start buying expensive parts. You could also check the timing belt to make sure everything is where it should be. I would just start going through the different system and determine whether they are adjusted/operating correctly. If you have a FSM--it should give you some ideas on where to start and possible causes.

hopes this helps

Henry

Joe R

thanks henry,

I'll clean the MAF, then start checking for vacuum leaks, although mechanic claims he did that.

Joe

tommytuttle

I had a similar issue, I had a check engine code. cleaned the MAF etc.. turns out I had a very small exhaust leak right behingd the cat and that was throwing off the computer. I put a patch on that joint.. and all good now.


just a thought.

Joe R

Interesting -- Exhaust system looks solid, but I guess it could be something like that. How did you figure that one out anyway?

Two things about my problem: I think is is heat related (only happens when engine is warm); and something tells me that replacing two O2 sensors in one year is a clue -- don't know what though.

fireteacher

hope you get it fixed and PUT MORE MILES ON IT! geez...31k on a 2000!!!
WOW

5-spd for life!

I just had the exact same issue on my 4runner. I have 150K miles and when I would start the car my idle would hang around 1500-1800RPM but when it would get warm I would have the same problem as you. It would always stay at 1500RPM until either at a dead stop or right before(1-3mph), and then like magic it would drop to about 1100RPM. I replaced my IAC and my TPS for good measure and now the problem has dissappeared! I also had no CEL's.

Clean your throttle body and MAF first!

DONT RPLACE YOUR THROTTLE BODY!!!!!!!!!!!!!!!!!!!!!!
(that is not what is wrong!)


Even if your throttle body gasket was leaking like a sive, then your car would hesitate and stall because it would be a massive vaccum leak, so dont let that mechanic make a fortune off of you! Your car runs good and it idles high but it runs, so your throttle body is at least doing it's job.

BruceTS

Your throttle body should be the same as mine, the Idle should be around 650-700rpm, except when you turn on the AC/heater, then it'll go up to 1100.

The odds are it's the TPS........ but it could be any number of different things as well.

tommytuttle

How do you test for a bad TPS? Can you clean them?

Joe R

thanks guys,

I think what I will do is clean the MAF and check the throttle body to see if it needs cleaning also, then I might replace the TPS just to make sure that isn't it. The thing about the TPS that confuses me is why would it work when the engine is cold/cool, but not when it is hot? It is not a temp controlled sensor, or is it?

I agree, no replacement of the throttle body necessary.

The car was bearly broken in when I bought it last september with 23K on it. The owner had three toyotas, and this was the only 5 speed, which he didn't like driving. Other than this idle problem, which is not a huge deal but is bugging me, it feels like a new car. Oh yeah, I paid below book for it


Thanks for the advice.

Joe

rajin

u did not say anything about the EGR, I say take a look.

TRDatVT

What about the high idle switch for the A/C... If that goes bad im sure it could cause constant high idle situation.

5-spd for life!

The 4runners in year 2000 didnt have EGR valves. I would say that the problem is your TPS or your IAC. Since I think you said that you replaced your IAC I think that you should go the route of your TPS. Try unplugging it when your engine is running and warm, and make sure that it is doing the idle problem. If your idle does not change then bingo! You can try to clean it though, just spray it with throttle body cleaner or electric parts cleaner. It is easy to take off and it is only 2 phollips head screws. But the is 50 part from toyota and I would replace it anyways.