Help plz!!! fuse?relay?limp mode? 1997 swift
 

Hello everyone! I'm new here and would realy love to get some help if possible.
I bought an older suzuki as a gas saver, a 1997 swift, 2 door, hatch, 3 speed automatic, 1.3L

The vehicle had no problems other than brakes to certify and etest it-all done!

INITIAL Problem: other than aslight noise it makes once in a while when it accelerates (like an airplane takeoff sound - not loud , basicly sounds as if i have an intake-car is stock and simple and the air box HOSE pops out all the time possibly an air leak, or plugged?

Main problem: I tried to switch the stereos from the already aftermarket deck to another one i had (better one) basicly somehow made a short circuit. (+ve and negative joined up) - all of which i disconnected for the moment. AS A RESULT THE FOLLOWING HAPPENNED :SERVICE ENGINE SOON-YELLOW LIGHT CAME ON AND IS STAYING ON RIGHT AFTER YOU START THE VEHICLE, THE INTERIOR LAMP IS NOT WORKING, THE NOISE WHEN THE DOOR IS OPEN AND KEYS ARE IN IGNITION IS NOT HEARD ANYMORE AND THE MOST IMPORTANT PART- WHEN THE CAR IS DRIVEN FOR A BIT(ANY AMOUNT OF TIME) AND THE IS SWITCHED FROM DRIVE TO PARK OR NEUTRAL THE ENGINE IS STILL REVVING HIGH RPM'S AND IT TAKES SEVERAL SECONDS FOR IT TO SLOWLY COME BACK TO NORMAL MODE, THEN I SHUT OFF THE CAR.ALL OF THESE 4 THINGS HAPPENNED IMMEDIATELY AFTER I ACCIDENTALLY CAUSE THE SHIRT CIRCUIT. I WENT TO A FRIEND MECHANIC WHO HAS A COMPUTER HE TRIED TO HOOK IT UP BUT IT WON'T WORK (SO EITHER THE COMP. IS DISCONNECTED OR WHATEVER BURNED OUT (FUSE?) IS CAUSING IT NOT TO WORK.

tHE MECHANIC CHECKED THE MAIN FUSE BOX WHERE ALL OF THE BASIC 6 OR SO FUSES ARE-ALL GOOD (I DID SWITCH THE 60 AMP BEFORE THAT) HE SAID THERE MUST BE ANOTHER HIDDEN FUSE BOX SOMEWHERE WHICH I CANNOT FIND. HE SUGGESTED FUSE IS THE PROBLEM AND THE CAR COULD BE IN LIMP MODE.

cOULD SOMEONE PLEASE LET ME KNOW HOW TO FIX THIS PROBLEM I'D APPRECIATE!