nfenwick

My 4Runner has recently developed an idle issue. I have a 3.4L. Normally when the truck is started winter or summer it runs at a high idle for several minutes and slowly starts to drop to nomal idle of 700 rmp. Now when I start the truck it runs at a high idle for a cople of seconds and then drops to normal idle which is causing a stumble and rough idle. I have removed the throttle body and cleaned it and the IAC. I did notice that the clicking noise that I normally hear in the area of the charcole canister I am not hearing. Any idea as to what I might need to look at? Thanks in advance for any help. Oh, post questions because that will make me think about things and maybe come up with a solution.

brian2sun

I had that issue about 4 or 5 years ago and had trouble pinning it down for months. At some point I replaced my front 02 sensor just for maintenance and my high idle has been normal ever since. Can't guarantee this will solve your problem, but it worked for me. If you have 80-100K on your 02 sensor, I would replace it anyways.

Another possiblilty is when you cleaned the IAC, did you use RTV silicone to seal the solenoid (or whatever it is) to the valve? If not you could be pulling air through there and it may be screwing with the valve or if you used too much silicone, it can prevent it from functioning properly. Good luck!

nfenwick

I have resolved my issue. Before anybody yells at me I was not completely forth coming in my original post. I left out one piece of information in hopes that someone would mention something that would change my train of thought. I appreciate brian2sun's post. What I did not mention is that I had purchased and installed a 'White Lightning' E85 conversion kit. Last night I went home and removed this kit to see if it was the problem as I suspected. After removing the kit the truck returned to normal operating procedure. I was concerned because I had half a tank of E85 on board and figured the CEL would come on. I took the truck on a 5 mile test drive including intersate travel and nothing. I was watching the timing, fuel trim and the OX2 sensors. All appeared to be working as expected. What I did notice is a remarkable improvement in performance. I will be glad to suffer a small drop in fuel milage for the gain in performce. The truck idles a smooth as silk. If anybody is concidering one of these kits I would recommend not looking into the 'White Lightning' kit. I think there are major problems with their electronics.