stuck throttle

So I was driving to can-tire today, and as I turn onto 72
st my throttle stuck full open, (I can confirm that the 88
4cyl has a fuel cut-off around 7000 rpm) any Ideas what
might cause this? after I closed the throttle it worked
fine for the rest of the drive so my car still runs.

The Fieros have a single butterfly valve in the throttle body. In the 4cylinder cars, there is also a single fuel injector.   The butterfly valve is controlled by a cable where the other end is wired to your gas pedal.   

A throttle can stick open if your cable gets dirty and the resistance of the cable is higher for the spring, which provides force for the butterfly valve to close.

Or the butterfly valve bearing is just dirty.

Try cleaning your throttle body, particularly at the bearing where there are moving parts. Check the tension of the return spring. Then check that your cable is not frayed or dirty.

The 87-88 throttle body for the 4 cylinder cars is different than the 84 to 86 units. So I don't have a picture to show you.   Sorry