High idle 1 minute after startup 02" 3RZ-FE 2.7 prerunner?

134k on ODO. High idle started recently. No check engine light.
Starts up fine with smooth lower idle then rises slowly to smooth high idling after about a minute. Stays that way after warmup.

Accelerates fine, AC and defroster not on.
I think its audibly high and abrupt when shifting out of park.

Tried removing and cleaning IAC and throttle body recently. No change.
MAF sensor and PCV cleaned 3k ago.
Air filter still good, tried spraying carb cleaner around vacuum hoses and Throttle body connector boot at idle to check for leaks, no fluctuation. Loosened the yellow painted throttle stop allen head screws to hopefully adjust, no effect.
Doesn't appear to have any hangups near the accelerator pedal inside the cab.

I guess will go to Autozone for a free code read?

Some threads found success with thermostat replacement, throttle body replacement, just don't want to throw parts at it if someone here has had the exact symptoms and fix. Thanks

 

Just making sure we on same page.


Engine is at normal operating temp
Air filter and all hoses are attached.
All accessories are turned off
Transmission in neutral
hold RPMS at 2,500 RPM for 90 seconds

Now check your idle, you should be at 700 +- 50.

Here are two links on how to check your IAC and engine coolant temperature (ECT) sensor

http://www.markofshame.com/fsm/03_Tacoma/Repair_Manual/03tacoma/sf2rzfe3/iacv/insp.pdf

http://www.markofshame.com/fsm/03_Tacoma/Repair_Manual/03tacoma/sf2rzfe3/ects/insp.pdf


My understanding is the IAC is pretty robust and doesn't fail very often. How did you determine yours was good after the cleaning? Look at my .pdf I linked you, when I performed that test, my IAC made a little vibrate sound but didn't move the window open everytime i performed the test, maybe only 50% of the time. My symptom I was chasing was extended crank times, and it fixed it.

Hopefully when you cleaned your Throttle body, you removed your IAC so all that gunk and cleaner didnt enter your IAC.


The more common problem i've found on the forums is the engine coolant sensor on the back of your head. You wouldn't know is there unless you reach around back there and say at least 3 curse words at Toyota Engineers. The multimeter test is very simple to do, make sure you have a new crush washer handy when you pull the sensor.

 

So if a scan gauge or the like shows what appears to be correct temp readings does that mean the ECT is good?

 

One would think so? But there are two of the coolant sensors, I'm not sure what sensor does what? It was easier for me to just unbolt the sensor and test it with my micrometer then to Google all of it.

 

I did some searching myself. Didn't know there were two sensors so thanks for that info. Assuming accuracy of posters in link below, which I do not doubt, the ECT on the back of the engine is what the ECU reads and the sensor on the front of the engine just connects to the dash gauge.
https://www.tacomaworld.com/threads/engine-temperature-reading-for-a-2-7.633268/

So my thought is if you have a scan gauge or the like and it's reading what appears to be correct operating temp then the ECT sensor is probably not the culprit for an IAC not working.

 

Interesting, I tried researching that and failed, good find

 

Thanks for the reply. Not sure how to check idle speed the truck doesn't have a Tach. It won't lower to idle like before even after driving it over 30 miles.
Yes, throttle body was removed before removing IAC.
Just assumed I cleaned it well but you have me thinking as I just sprayed it and used qtips but wasn't spotless.
Ripped the connector boot and waiting for a new one then probably take it off again and try to hook it up to 12v and look for movement.
Still have to check for codes probably should have done this first even though no check engine light.

 

So Woad4 thanks as you got me thinking if my cleaning of the IAC was thorough. It was not.

Leads hooked up to the battery and no movement.

Took it off again and cleaned it again with lots of q tips and carb cleaner and some toothpicks and the handle of a plastic spoon wrapped in paper towel soaked with cleaner.
Then used a dremel to cut a slot in the weird torx type screws in order to remove the motor side with a slotted screwdriver.

There was alot of drag and carbon streaks on the swivel door so kept on cleaning until it spun freely.

The motor side removal exposes a pressed in bearing so I put a couple drops of turbine oil on it before reassembling.

Connected to a 12v battery charger, the door will close when hooking up the - lead to the top side connector/+ lead to middle.
There is a slight hum felt in the closed state.

Can tell its closed as i put my mouth on it and felt resistance blowing into the port.

Otherwise it stays in an open position when not connected to power or when the neg. lead is on the bottom.

Changed the plugs since everything was apart. They looked fine but were platinum and the new ones double iridium.

Have to get another intake gasket before reassembly.

 

Solid work, sounds pretty similar to my experience. I'll cross my fingers for ya, keep us updated

 

All together and went for a spin. Idle back to normal.

The thorough cleaning of the IAC seemed to do the trick. Saved alot over OEM replacement. Could be the first time cleaning the throttle body without removing it gummed it up.

Gotta stop doing things half assed lol.
Did it the right way by removing all the plumbing between the air filter box and intake. Made access to bolts and plugs easier.

Also makes removing the connector boot simple without distorting it and damaging it lesson learned.

Having the right extensions, wratcheting combo wrenches and hose pliers made the job easier.

Broke the clip for a rear elec. connector but will put a zip tie around it.

Tacomaworld.com is the shiznit! Thanks!

 

Yoooo!!! Solid work! Glad it's working!


I finally helped someone fix something for once. My advice usually ruins trucks