IAC Valve

97 Tacoma 2.4 Automatic
The truck has dangerously high idle speed. Reading online, the IAC may be the place to start. However, I can't find a walk through for this. Does anyone know of a posting for this particular model and year....or any suggestions.
TIA

 

Welcome to TacomaWorld.

Might help... pg 6 has the IAC but also included is TPS and MAF (covers 95-97 I believe). Good luck troubleshooting.

 

https://youtu.be/agIRNNA-6cs

 

Major differences between the 3.4 and 2.4? OP has the 2.4. Serious q since I have the 3.4 and wouldn't know.

 

What are you considering dangerous high idle speeds?

The IAC is the place to start, but if you're saying "dangerous" then it might be a combination of sensors that need to be inspected (you should find yourself a digital copy of the FSM, if you search here, there are links), cleaned, and/or replaced.

MAF, TPS, and IAC, 02 sensors all play a role in the idle.

However, I would also suggest inspecting and replacing your vacuum lines. Something often over looked is the brake booster (it's vacuum-assisted- connected to the intake manifold)

Edit: The ECU's in these trucks are sensitive to the brand of sensor you have. Replacement sensors should only be from Toyota or a widely recognized OEM supplier (Denso, Asin). So if you replace something like your MAF, be sure to get an OEM part, otherwise you're likely just creating another issue.

 

Looking in the FSM- the throttle body looks similar. The Timmy video should give the OP the right idea, but yeah, he needs to follow the FSM for the specs.

 

Any codes? Clean the maf, iacv, & throttle body.

 

By dangerously high, I it will move from a stopped position even with heavy pressure on the brake.
No codes...well I have an intermittent code that pops up and causes other issues. A cam sensor...saving that for later posts.
I am going to do all you suggest, but after having hell on the water hoses I may replace with OEM so I don't have to do that again.

 

mmm... I thought to add this earlier but got distracted. Check that your throttle cable is not too tight, and can move freely (soak it in some dry lube- something like DuPont Non-Stick Dry Lubricant, not wd40, which will attract more dirt over time).

 

Thanks for files Area51Runner.
Truck doesn't have tach, maybe a future upgrade.

 

Should still be the same with respect to troubleshooting as well as the sections on the MAF and TPS. Hopefully, something you can use to get you where you need to be.

Andy put some good info forward. I'd check his suggestions as well.

 

Sounds like you have some brake problems as well with the brakes applied the truck should not move no matter the rpm.

IAC problems should trip a PO505 code

Mechanical issues will not trip a code

I would really check the throttle cable throttle body valve hanging up or sucking in air .

 

Andy
Thanks for the suggestions and the heads up on using OEM parts.
Aftering pricing the IAC, I am going to try the cleaning route first and will check on the TPS, MAF

 

Yes, the OEM parts are expensive. But the non-OEM parts don't play nice with the ECU.

I also don't think the IAC alone is going to cause an excessively high idle as you're describing - so I can't stress enough to be looking elsewhere for the root of your issue.

 

Did that to my '97 5 lug years ago. Found a speedo cluster from a newer 4x4/prerunner (early 2000's iirc), and it dropped right in. I did it in the parking lot so I could return it if it didn't work.

Worthy upgrade. Just keep track of the miles. I suggest using one of those label maker things to write down the mileage conversion and stick it next to the odo.

 

Andy..OEM only for me. Read too many problems going cheap route...although the OEM radiator and master cylinder were not out of line price wise.

 

Ok. Sorry for the delay. Had to order gasket and wait for a break in work.
I should have taken a before picture of the IAC and throttle bottle. It was horribly gummed up, oily, and every moving part was sluggish. I cleaned it and it runs better but I need to test sensors as was suggested. I am ordering a real meter; I don't really want to trust my $3.99 Harbor Freight on this.
The truck is doing better, still high idle but noticeably less.
Also, and I am going to do a postn this later: I get an intermittent check engine light. The motor will get somewhat sluggish and the a/c will quit (not good here in Louisiana).When the check engine light goes off everything is back to normal.
I got a code for camshaft position sensor. Since the IAC cleaning the check hasn't come on,but I haven't really driven it for a long distance. That will change tomorrow. I intend on using for work tomorrow, and that should tell the tale.
Could the two be related?
As always, thanks for your help.

 

yes the two could be related

 

start simple

 

Check all fuses and wires