Wont go into gear 88 fiero gt?

I had a 88 myself and had the same problem, look down inside the console by the shifter and there is probubly change that has fallen down there. Hope this works for ya

There are a few more things that can be wrong, but the most common seems to be the shifter cables. The 88 GT came with 2 cables, both of which are NOT adjustable (and stretch with time), and no longer available to purchase (stock). As they stretch, they lose effectiveness. You can buy replacements that are adjustable (and come fairly accurately adjusted) from RodneyDickman.com. Good luck. I had no one to get advice from and spent a TON of money having my hearbox torn open twice to replace all the gears and synchros before I finally figured this one out. Don't make the same mistake.