Help Please With Is300 Very High Cold Idle Speed!

[Dennis Lam]

Hello, Can anyone help with my IS300's very high cold idle speed?

I have a 2004 IS300 sportcross auto, which has only recently (in the last 2 weeks) started to idle very fast 1250 to 1400 rpm when started up from cold (first thing in the morning or after it has been parked for a couple of hours), until two weeks ago it idled very happily at 650/700 rpm in D when cold or warm.

I looked on the forum and followed the suggestions posted so I have today cleaned the MAF sensor, cleaned the throttle body, checked linkages, the car was serviced in July and the air filter was changed then, but after cleaning everything today the engine is now idling even faster on a cold start and now the idle speed only drops back to between 800rpm and 1000rpm when the engine is warm?

I also noticed that, since cleaning everything, when warm, the idle rpm (with the car stopped and in park) is 800 - 1000rpm with the a/c on but over 1100rpm with the a/c switched off?

Can anybody suggest a cure/remedy for this as has only happened in the last couple of weeks and I am having to constantly hold the car on the brakes when in traffic as it tries to constantly pull forward until the engine is fully warmed up.

Thank you all in advance, any help would be very much appreciated.

Dennis

[Rory]

mine is the same, apart from the aircon bit, drops after about half a minute tho so i've never bothered, had the car 18 months and it hasn't gotten worse

[Guest]

I don't know if this would help!

My MR2 used to do this when the alternator/battery was on its way out. The Battery light on the dash didn't light up until the alternator died. but with new alternator the high rev stopped. similar situation happened on my other car and a new alternator stopped the revving.

Just a suggestion I'm sure a genus like "knitware" or someone will be along to provide exact details of what it is.

[Silversalmon]

My Sportcross has done this for a while, remember I'm in Scotland where it is colder, when i start up in my drive i find it helpful to use the snow setting as i don't want to fly out into the road! Perhaps it's a cooler weather thing only?

[Dennis Lam]

My Sportcross has done this for a while, remember I'm in Scotland where it is colder, when i start up in my drive i find it helpful to use the snow setting as i don't want to fly out into the road! Perhaps it's a cooler weather thing only?

Hello Rory, Stefan & Edward,

Thank you very much for your suggestions, I know that the Battery was changed in June and the alternator was checked and found to be fine, so I don't think that the battery/alternator is the problem on my particular car. I will take up the suggestion of starting off in the 'snow' mode. It is quite possible that this very high cold idle is weather dependent as during the summer it ran fine and it has only been misbehaving these last two weeks since the weather has cooled off, though I am really not looking forward to driving the car in the snow and ice if this problem persists.

I had a 2000 LS400 mk4 for over 5 years and in over 80k miles it never missed a beat or played up at all apart from needing a new Battery at 126k plus the normal service items, I have only had the IS300 since the end of June and miss the old LS battlecruiser, in city driving both cars only managed 17/18mpg, on the motorway the LS was actually more economical as I normally achieved between 28/32mpg but the IS300 barely manages 26/28mpg on the same routes.

Thank you all for your kind suggestions.