ramayah Posted December 29, 2016 Share Posted December 29, 2016 I have a 1994 GS300 with 144K miles. At startup on cold engine it revs up to 1800. After a few minutes it drops to 1000. At normal temperature and in drive it idles at a very steady 800. Shouldn't it be idling at about 650 at startup and in drive? It never used to do this about a few weeks ago. Your help to diagnose the problem will be much appreciated.Thanks Quote Link to comment Share on other sites More sharing options...
TrevC Posted December 29, 2016 Share Posted December 29, 2016 Hi Randolph....welcome to the Forum On start-up the idle should be increased to around 1200-1300 rpm (raised idle) to speed up the engine/catalytic converter warm-up process. Should last for around a couple of minutes maximum. Something may be sticking in the idle control circuit if its that high...carbon build-up? Keep us updated on what you find. Cheers Trevor Quote Link to comment Share on other sites More sharing options...
ramayah Posted January 3, 2017 Author Share Posted January 3, 2017 Hi Trevor, I took my 1994 GS300 to the shop. The mechanic told me that the Idle Air Control valve needs to be replaced or cleaned. It's quite normal for it to idle high at start up on a cold engine and not to worry about it. However, if it bothers me then I can take it back and have it cleaned or replaced. It will not damaged the engine by running high at start up. So I'll leave it as is for now. Thanks for your input. Randy Quote Link to comment Share on other sites More sharing options...
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