Weird idle phenomena??

[Aurion fi]

I have a 1998 camry v6 auto csi.

It just clicked over 100,000km..

I was taking a photo of the odometer at 99999... when it clicked over to 100,000km it all of a sudden had a crazy idle??? Bang on 100,000km it started. 

It was all over the place idle from 500rpm to 1000rpm.. up and down.. engine was shaking..

I had air cond on a time. I turned it off, turned car on and off but still did it.

Drove car about 2-3km and it was driving ok but idle was shocking.

I stopped into petrol station and was looking under hood. Undid air box and i could hear it sucking, stopping, sucking again..

I returned to drivers seat and held revs to about 3000rpm. Then revved it to 5500rpm or 6000rpm..

Then all of a sudden idle was right.. perfect again.??

Stopped and started and all good. By this time car had 100,003km on odometer. Car ran perfect for rest of day and i did another 95km.

Weird phenomena as it hit 100,000km exactly?? It went crazy.. Does computer reset or something as it reaches certain points over the odometer? Or just coincidence?

[Aurion fi]

Perfect at 99,999km but went crazy idle at 100,000km

[campbeam]

I reckon that it is sheer coincidence. My 1998 Camry 4 cylinder was idling fine at a set of trsffic lights after a 60km trip of mainly highway driving then would not idle after stopping at the next set of traffic lights after just 2kms. Solution ended up being to clean the throttle body and idle air control valve which had not been done since new after about 150,000 kms. Those items are now on my annual maintenance list for all of my cars.

[Novicebutnice]

It sounds like the engine is "hunting"

What fuel have you been using, it could be a bad batch,

Otherwise I would replace spark plugs and clean the throttle body as a start.
 

[Aurion fi]

I did fill it with 95 octane fuel about 20 mins beforehand. Usually use 98 octane.

Shouldnt be a problem though as they are ok even at 91 octane.

I have cleaned throttle body etc about 500km ago. I did again this morning but its all sweet now. Weird phenomena

[Aurion fi]

I did fill it with 95 octane fuel about 20 mins beforehand. Usually use 98 octane.

Shouldnt be a problem though as they are ok even at 91 octane.

I have cleaned throttle body etc about 500km ago. I did again this morning but its all sweet now. Weird phenomena

 

Anyone think it could be air cond? Car was stop start in traffic a fair bit at the time. Could it heat up too much? 

It just was all over the place with the idle. Up and down hunting from 500rpm to about 1000rpm.

[Novicebutnice]

2 hours ago, Aurion fi said:

I did fill it with 95 octane fuel about 20 mins beforehand. Usually use 98 octane.

Shouldnt be a problem though as they are ok even at 91 octane.

I have cleaned throttle body etc about 500km ago. I did again this morning but its all sweet now. Weird phenomena

 

Anyone think it could be air cond? Car was stop start in traffic a fair bit at the time. Could it heat up too much? 

It just was all over the place with the idle. Up and down hunting from 500rpm to about 1000rpm.

If you had been using 98 and then went to 95 the engine could be trying to "sort itself out" they usually do a minor re-map when you change fuel 

 

[ZZT86]

I suspect some contamination from somewhere, IAC possibly needs cleaning, perhaps an O2 sensor that is starting to play up. Idle is normally solid with bugger all variation regardless of octane, play it by ear & see how it goes.

Edited October 21, 2018 by ZZT86

[jeffy]

Try using this: 

https://www.supercheapauto.com.au/p/fuel-doctor-fuel-conditioner---275ml/120027.html#q=fuel+doctors&segment=1&page=1

 

maybe reset the ECU?

Also:

https://axleaddict.com/auto-repair/How-Do-You-Know-if-a-Throttle-Position-Sensor-is-Bad

 

ive also typed in "idle" in the search forums and found other members with similar situations have a look:

https://au.toyotaownersclub.com/search/?q=idle

https://au.toyotaownersclub.com/forums/topic/56142-05-avalon-stalling-and-low-revs-on-idle/?tab=comments#comment-569825

 

 

[Aurion fi]

Update..

 

Has not done it again. I noticed the air box was not closed properly. Where is clips in wasnt in so letting in hot air.

It could be just a mixture of cold air and very hot underhood air going in concurrently? 

Ive fitted it up and checked tightened all intake pieces. Perfect idle for a few days.. drove 4-5 hours the other day and perfect