High Idle and found this piece on the ground

After changing the head gasket on my 2.4L 1996 Tacoma, the engine idles very high. Last thing I installed was the Fan Shroud, and after that, I found this piece of rubber hose on the ground. I can't figure out where it fell from, and if it's actually what's causing the idle to be very high. I did clean the Throttle Body very well, and deleted the EGR while I was at it. I'm also getting a P0325 DTC - Knock Sensor Circuit Malfunction (Sensor 1, Bank 1). I'm not sure if anything is related to each other. Any help is appreciated. Thanks in Advance.

 

Looks like a PCV hose, if that's indeed what it is that would definitely cause a high idle because it would be a big vacuum leak.

 

Could be off the dash pot.

 

I think I found where this rubber thingy goes. 99% sure it goes to the coolant overflow tank.

 

Look for a vacuum leak. It will be sucking air

 

That code is straight up knock sensor/knock sensor pigtail or harness

b4 I would work on high idle condition,
RR that sensor

IMO that hose is from coolant res dump hose…..100%

 

Seems like two different issues.
I’d get the code fixed first, and then start the high idle hunt.. since you just had the head gasket done my first guess would be a vacuum line somewhere got cracked or forgotten during reassembly. Or IACV may need to be cleaned if you didn’t remove it for cleaning when you cleaned the TB.

Also start watching for any other weird issues or changes from before, with high idles there can be so many causes that sometimes the best way is to look for a secondary issue that’s being caused by the same thing as the idle. Just as an example I was only able to track down my high idle by noticing the engine was a few degrees too cold and it turned out the thermostat was bad causing both issues.
So keep an eye out for anything else weird going on and if you notice anything throw it in here and it might help everyone figure it out.

 

what was your idle at When the thermostat was bad? Asking for a friend..

 

My idle was around 1750, and coolant temp was 155-165 instead of 180-190.

 

Agree with time623 about IACV

mine was absolutely nasty
Appears that rubber gasket leaking too