92 Ford Mustang Idle Issues

I have recently acquired a 1992 ford Mustang with 149,000 V8. It has been negleted for quite some time. I have gotten her to start and all seems well except for the annoying issue of the idle, @ idle reads 3200. It almost sounds like it IS at 3200 but could be @ 1000 ish. Once you drive and it IS above 3k, the tach moves like normal. When you turn the car off, it goes down to 0. And the car surges and lurches the entire time below 25 mph. Once you give it some gas or a load (up a hill) all in fine. It had 30lbs fuel injectors and some wack cold air intake (it was pieced together with odd and end pieces) So the injectors are back down to the stock (19 lbs) and the intake is back stock. The only thing different was the pedal control is super touchy and take off is much faster. There are no vaccum leaks.
Is it time for sensors, or tach, or?
It has been 3 months with all the researching and tips from everyone, ANY help would be thankful.