I have90 Miata. The probem is I have screwed the idle screw all the way in and it is still idleing 1100-1200 rpms. I cleaned the throttle body and iac valve below it. I also cleaned the valve on the side of the intake which has 2 water lines running to it. I am not sure how to test them to see if they are working or not. On the IAC valve I disconnected the connector and there was no change in the idle. I am in the right area for the problem? Help please?

 

if you have done every necessary step in solving your idle problem, i would suggest a good tune up, everything that is involved in a tune-up....it could be that the car just has a lot of wear and tear on the motor and this is the cars way of letting you know that something is not quite right.....if your car has a lot of miles, then this could be what it is...i read on-line before i started tuning my miata that if your car is idling high, it is not a good candidate for tuning....i hate to say it but think about it....if you continue to run the car with the idle problem at hand, it might not last you too much longer....it is never a good idea to unscrew the idle screw to try to fix the problem.....if the car is idling high then there is obviously something very wrong...unscrewing the idle does not fix the problem, it is trying to make the car idle at a lower rpm with the existing problem still occuring.....i would take it to a mechanic....