Car was idling at 900-1000 rpm in Park/Neutral. First i tried replacing the idle control unit with used one from eBay and cleaned the idle valve with carburettor solution. When i first started the car the idle was down to 600-650 rpm in park/neutral and i thought the issue was fixed. But after a while, the problem became worse, it now idles at 1400-1500 rpm.
This is what i found:
The voltage at the idle control valve is 4.4 , resistance is 10 ohms. When i remove the connector to the valve, the rpm raises above the 1400rpm to 1800rpm and when 12v is applied at the leads, the rpm cuts and the engine almost stalls. So looks like idle valve is working.
Also, if i press the idle control unit at certain place(on the smaller upper board bottom right corner) , rpm drops and if i press hard enough, engine stalls.
How to absolutely confirm it's the idle control unit that is the cause for the high idle?