I've referred to this in another thread but thought I'd give it a thread of its own especially in light of some new evidence.

The car MY00 UK classic has had a slightly high idle for some time when the engine is warmed up: it settles at around 900rpm only dropping to 750rpm after some time. I've cleaned the ICV on several occasions but to no avail and looked for leaks in hoses etc.

Today I noticed that the high idle is related to the use of the heater (possibly also the stereo). If blower is on 1 or above and then I switch it off (0) the idle drops to 750rpm, turn it on it rises to 900rpm.

I don't know much at all about car electrics but it suggests something is faulty. Any suggestions what I can check?

Thanks

 

Well when ever you turn electrical stuff on you put load onto the engine and the engine compensates this by giving the engine more juce. I belive this is controlled by the idle control valve (something like that) but the engine RPM will recover quickly and should settle back around 750rpm. I wouldn't of thought it's straight up the electrics maybe more like a vacuum leak, I had a a focus with a broke MAF sensor and that caused high idle and also the Engine to hunt.

 

Thanks. I changed the MAF last week and that didn't make any difference. It's weird - I can adjust idle speed by turning the blower on/off...