I know M42 engines are known for funny idle, but curious what yours is.
I have been playing with the set screw for the top throttle, as well as the set screw for the ICV (you can chip the brass screw out of epoxy on the ICV and then adjust it to set the gaps in the ICV.
The computer is smart enough to always revert to the same (low idle speed).
What I generally see is this: A normal idle speed of say, 550-650 (is there a good way to get the actual speed besides reading the tach?). AC relay clicks on, engine speeds up to about 800, then slowly dies down to about 600. Relay clicks off, speed drops a bit to about 550, then picks back to about 600.
This happens over and over. Typical? has always been this way since Ive owned the car, which is about 10 years and 70k.
But the low idle bothers me, especially since all rubber is good, ICV is newer than 2006, O2 sensor from 2004, no leaks, squeaky clean emissions, good MPGs.
Normal? Abnormal? No idea what is or isnt...
Any insight is appreciated.
Thanks!