Suzuki: 1990 SUZUKI SIDE KICK, suzuki side kick, kick two

Question
TWO QUESTION ARE IN NEED OF SOME ANSWERS FIRST OF ALL HI ARE YOU DOING THAT WAS NOT MY QUESTIONS.  ON MY SIDEKICK MY ENGINE IDELLS FINE AS LONG AS I DONT TURN MY AIR CONDITIONER ON ARE TURN MY SOUND SYSTEM UP(LOTS OF AMPS. AND SUB. WOOFERS)BUT WHEN I TURN THEM ON OR UP MY ENGINE LOOPS UP AND DOWN (500 RPM TO 2300 RPM).  AND WHEN I DRIVE MY TRUCK ON THE INTERSTATE(WHICH IS A 70 MILE PER HOUR ZONE) I HAVE TO BRING MY TRUCK UP TO SOME VERY HIGH RPMS IS THEIR A WAY THAT I CAN CHANGE MY GEARS IN MY REAR END TO MAKE IT WHERE I COULD CRUISE AT 70MPH AND NOT HAVE THE RPMS THAT HIGH.


               THANKS ALAN

Answer
There's an electrically controlled air valve on the side of the throttle body.  The service manual has a rather long and somewhat complicated adjustment procedure that does work relatively well.
As for the gearing, consider whether you can afford to sacrifice some hill climbing power to get lower revs.  If you live in a relatively hilly area, you might not like the trade-off, but if you live in western Kansas, or another equally flat region, it might work out.  
IZOOK.COM has lots of links to parts and modifications people.  My personal favorite is rocky-road.com, but then that's because they have loads of Samurai stuff.  They do have a fair selection of Sidekick/Tracker as well.
Scotty