Didn't he just say, adjusting the BISS wasn't helping? I thought I read that. Two Mitsu techs told me that we shouldn't be turning the BISS screw very much if at all from factory specs. Usually, the issue is unrelated to the TB, and the BISS is only there to compensate for clogging ports in the TB from age before it needs to be rebuilt or replaced or an aging ISC and/or deposits in the ISC port.
Clint, you act like I am talking out of my ass. I know these cars as well as you do and have been tuning mine and others since 99. I am not a newb and there are many ways to skin a cat. I just prefer the most direct route that isn't going to make your ISC max out or drop to nothing when the guy already said the BISS is not helping.
I just think if a person does not have proper knowledge of all the functions of the throttle body and the proper way of setting them, they should never attempt to touch it themselves.
The SAS can be adjusted and is the better alternative to fixing a low idle over the BISS adjustment assuming you have eliminated all the other causes for a low idle which may be caused by an improperly adjusted TPS, a malfunctioning ISC, poor charging or leaks either withing the TB mixing body, clogged bypass orifices, or a leaking BISS port.
You have disagreed with me in the past, and it doesn't bother me because I know what I am saying works and its been tested on many cars with satisfactory results. The manual is not incorrect. They just recommend you leave it at the factory setting, but wear of the SAS screw where it contacts the throttle linkage can and will drop your idle speed after a decade of use. If he is at 700rpm, a slight turn of the SAS screw and an appropriate adjustment of the TPS will fix the issue assuming he has no leaks.
PS---Many people should be replacing their throttle bodies after more then 100k miles on the clock, especially on a turbo car that has spit tons of oil and blowby through it. Wear on throttle shafts, leaking BISS port, hardened carbon deposits in the mixing body, worn throttle plates, all these things will make it go bad. You can rebuild it and replace the sensors or just replace it as an assembly like I did with mine. My car runs so much smoother with a new throttle body that I am pissed I even wasted the time cleaning and adjusting my old one.
Sam