Hi, Im new, but i have the SAME problems in my SVX, I think I put around $700 into trying to fix it with NOTHING to show for it.

DONT SWITCH YOU MAF SENSOR OR YOUR OXYGEN SENSOR OR YOUR SPARK PLUGS, UNLESS THEY NEED REPLACEMENT FOR SURE. I SWITCHED OUT ALL THREE AND AM STILL HAVING THE SAME EXACT PROBLEM!!!!

If the same is happening to anyone else, which is this.....

when your driving, a loud whistle from the engine comes on. I go check the vacuum lines, and there are leaks ALL over the place. Im about to have ALL of them tightened to the max, and ill let you all know what happens.....