I have a Lancer 2004 (4G18 MT) that I bought in 2008 and I'm having issues with its RPM.
First the RPM kept dropping (400 or even lower and sometimes the engine just stopped) even on neutral gear and I read up online and learned about cleaning the throttle body with carb cleaning liquid. That helped and I read some more and found out about cleaning the IAC and did that too. Now the RPM is very high (even after adjusting the screw on the throttle body) and goes upto 2,000 on cold start and even on cruise speeds (latter when the engine is hot) but stays at 1,000 on neutral gear. Turning on the AC does make the RPM change and it comes back to its previous level in a few seconds.
Help needed: Mileage is too high and the RPM keeps dropping from 2000 to 1000 on low gear (nightmare to control the car on Shahrah-e-Faisal heavy traffic).
Please suggest what I should do/see to get this issue fixed.
Guidance and Questions will be much appreciated!