My auto YRV is a domestic Japanese vehicle imported into New Zealand and has had an erratic idle for some time. It is not a major problem,more annoying than anything.
Starts fine from cold and runs at about 1200 rpm and when up to temperature goes to target idle of 700-750rpm. However stop the next time it could go down to as low as 400rpm or up to about 1000rpm and then sometimes to the target idle. Its a bit like a lucky dip,you never know what you are going to get.
I checked the electrical supply and came up ok as per the Daihatsu service manual. I removed the coil unit to check out the idle control valve, as shown under EF-134, to clean if it was possible. And of course nothing to clean. The shaft with magnet on the end can revolve 360 degrees. Is this correct as there are two locations for the magnet to fit into the coil unit?
Used throttle body cleaner on the butterfly valve and in the auxiliary air port but made no difference to idle speed. Butterfly valve is fully closed and just touches the throttle stop. As someone has had a go at it before there is no paint mark on the grub screw adjustment only on nut.
Any help would be appreciated.
On sadder note Toyota have announced they will no longer be selling Terios and Sirion from the end of the year. However,there will be a good supply of 2nd hand Sirions or rebadged Toyota Passeos imported into New Zealand.