Binding throttle or vacuum leak. I'm guessing it's a vacuum leak.
There is a corrugated metal tube that goes from the exhaust crossover to the bottom of the orange intake manifold neck. Those tubes are famous for cracking just below where they bolt to the bottom of the manifold neck. http://rodneydickman.com/ca...h=22&products_id=308
I see that you are near Huntsville. About 10-12 miles north of Huntsville (in Toney) is the Fiero Factory (now aka TFF Automotive.)
If you go north on 53/Jordan Lane, it's on the right, after you get out into the country. If you get to Tennessee, you've gone too far.
They have most any part you would need. Kind of spendy, sometimes, but they know Fieros very well.
[This message has been edited by Raydar (edited 10-18-2014).]