Vitara 1991 brake booster replacement

[fixkick]

idle and vacuum must be controlled and adjusted in the correct order. (repairs first then calibration)
healthy engine ,compression good, thermostat ok, spark timing set to spec. then below list.

1.  no vacuum hoses leak  or the TB base gasket, no things on end of hoses leaking air, "devices"   If 3speeD A/T the modulator hose end not leaking too.
   
2. TV gap set to 0.0005 to .0001" inch.
   
3. TPS idle switch set to .016" trip point.
   
4. IAC CLOSED AT 150F UP.
   
5. ISC NOT JAMMED UP, OR leaking grossly with damaged seat as many have now this old.
   
6. ISC duty cycle set to 50% by turning the air bleed screw front center of TB.
   
   

on this car and this ECU any gross air leaks may cause the ECU to go nuts.  it may even use the ISC to hunt idle RPM wildly. (trying hard to gain control and fails)