2rz problem

Hello. I am not getting to the root of my problem in the Gen.1 forum. Mine is a 04. Only a few years in Gen.1 with the electronics, fuel injection, etc.

Maybe you guys have some thoughts, ideas, or suggestions.
Here's my problem. Engine cranks fine. It seems to idle to high. On a cold day it seems to oscillate back and forth between a lower, then faster idle RPMs.
When I am driving down the road. The accelerator has a sweet spot. Its not very far down the pedal travel. Pushing down any further, it seems to loose power. As long as I don't mash down too far I am okay. This is not normal. It should accelerate more as I give it more gas.
When I check codes I see a Idle air control valve.
This engine sat up for a year and a half, and was recently re-installed in the truck.

Thanks in advance.

 

Sounds like you need a idle air control valve. Your symptoms match with it being stuck.

 

I remember on the older trucks you could tape over the hole in the throttle body on the inside and it would trick something with the iacv. I’m not sure a bad iacv will cause the throttle to have dead spots. The way your describe it sounds like a bad throttle position sensor. Unplug it and test run it’s a lot cheaper to replace if that is it.

 

This is some good thought provoking material. All this started when some major work was done on the truck. It didn't do this before. I want to check to see if the vacuum hoses on IAC could be on there backwards. Is there a in and an out?
If I don't find success there. I will move on to the throttle body sensor.
Thanks guys.

 

Sounds like an idle air control valve...Also, you might try cleaning the throttle body as well.

 

Unplugging, or re-plugging makes no difference. Same problem. (good idea, though) I got to dig a little deeper. Do I have the wrong wire going to the IAC? Am I getting the right signal to it? It is a mystery at this point. The you tube vids I watch on this has the RPMs dropping off. Mine is the opposite. High RPMs. I am tempted to crank the idle down, and ignore the problem.

 

You unplugged the throttle position sensor not the iacv right? The plug should be "keyed" and wouldnt allow for the wrong plug to be plugged in. if you do adjust the idle count your turns so you can go back if needed, not sure this is the right way to go about fixing it. Does it change if the truck is hot or cold?

 

I actually tried unplugging both. One at a time. The top one, would change the idle. Then go back like it was. This happened real fast. A fraction of a second. The bottom one. I believe that to be the IAC made no difference what so ever. The shroud on the bottom one is slightly broken. So it may be possible to have the wrong plug there. That would explain this problem. It is a 4 prong plug.
It is worse when cold. The RPMs wants to oscillate up and down just a small amount.
I am thinking I need to disassemble the intake, and inspect everything more carefully. I am likely looking for a stupid mistake. One made by me.