Can anyone adivise the most effect way to troubleshoot a very very irritating fluctuating idle?
I have a D16Z6 engine which is completely original ( no mods ), The idle speed fluctuates from 1000 to 1500 rpm when the engine is stone cold and doesn't improve even when properly warm. For some reason, from when it is properly warm and then the engine if turned off for 15 or 20 mins the idle is fine for a short while. It then reverts to the fluctuating idleas previously mentioned. I could just change the IACV but, I am told it could be a number of things other than this. What would be a good way to rule out or otherwise other causes please ?