ya if those theories don't work, check your fluid in your radiator and make sure its filled to the neck right before the ravine to your hose for the overflow tank and if that doesn't work, try adjusting your throttle cable because if its running way too lean or way too rich that will make your idle go really high and once your car idles at like 1300-1400 rpms it will start high rev-ving"which is when the idle goes up to 1400rpms and than just drops back to like 700rpms and keeps doing that" trust me I hated stopping at a light it sucked ass; I would just sit there holding the accelerator down a little bit just to keep the idle steady if nothing works than just keep posting back and let me know where your at and I'll try to keep helping you.

Oh and when you said your Idle jumped a lot when you turned your steering wheel, go ahead and tighten your adjusting bolt on your powersteering pump. Its the really long bolt(10mm) that runs from the top of your PSP"power steering pump" straight through, and down to the bracket that the PSP sits on that is connected to the head of your engine. Make sure that bolt is extra tight and just keep pushing on that belt to see if its almost so tight that when you push on it with your index finger it hardly or almost seems it doesnt move. than simple take a (12mm) wrench and tighten the lock nut right underneath the head of that bolt, tighten it down to the mount as well. Don't spend money yet try a few of these things first and you'll get it, goodluck