I have a friend with a 91 Isuzu pick up with 2.3 his motor does not want to idle right they have this box on the side of the motor with idle on it we sprayed some electrical cleaner and it idled perfect for a minute then went right back to the same rough idle i was wondering what does that box do and is it hard to find. Thanks!!!

 

proably have a vacuum leak,try spraying carb cleaner around the intake.if the idle smooths out either theres some broken hoses or intake gasket is leaking vacuum an the cleaner is being sucked in .