Quote Originally Posted by oj88 View Post
There's an Indonesian blog that mentions this problem and describes troubleshooting procedures here (Google Translated to English): https://translate.google.com/transla...-sempurna.html

This ISC valve is very similar to a voice coil or stepper motor (same operational principle to a speaker or a hard disk read/write arm) that allows the ECM to precisely adjust the idle speed. If the coil is shorted or open or has changed its resistance, it may not respond to the ECM's command properly causing it to work erratically. Either that or the problem could be mechanical in nature... ie. the pin/plunger/piston no longer travel in and out smoothly (see diagram below).



I'd put my money replacing the ISC if

1. The measured resistance across the pins are off-spec, or
2. The plunger binds or sticks
And do the proper relearn procedure