Hi.
NOTE: So, if your car has important mods, then say so in the original post!
Buy a repair manual for the car!
Also, you'll need a manual for an
'85 GT. I suggest the Ford repair manuals if you can get them on ebay. Otherwise, the Chilton's Manuals are a place to start. But, the info in a Chilton's often isn't very specific, and often not complete or very accurate.
As I remember, only Canada '86 5.0's had carbs. So, if your car has mods, then say so in the post. Many of use turn off the often obnoxious sigs.
IMHO, don't waste your money on a scanner. It won't even hook up to your car.
You have much bigger problems now. My suggestion is that you may be better off taking the car to a garage. And, don't be surprised if a garage will not work on the car, or doesn't have a clue on how to hunt down a problem with an engine that has a carb.
It's not impossible to find and fix the problem. But, IMHO, you'd have to get
very lucky as a new mechanic to find and fix the problem without putting a lot of time and
money into it. But, hey we
all have to start some time!
*I* started with cars with carbs, modified cars with carbs, and raced cars with cars. I still have a car with a carb - '69 Firebird. *I* am being
honest with you. There are
many things that you will likely have to to check and know about. If you have the time and money, then GO FOR IT!

That's what this
hobby is about!
But, if you think that you'll find some
simple answer in the forums, IMHO, you'll be better off posting an thread with an honest title like "Looking for someone to blow smoke up my ***!".
Good Luck!
If I was you, and I was going to try to find the problem, I would do the following in semi-order:
o Get a vacuum gauge.
o Get a timing light
o Check the spark plugs
o Do a compression check
o Do a leak down test
o Try Get a cheap carb (swap meet, junk yard).
o Try a new carb (~$150++)
Each bullet above has
many steps and is involved is
NOT something you will learn about in the forums.
Again, get a repair manual, and read up on how to do the tests and read the results. Back when mammoths roamed the Earth

, and there wasn't any Internet, that what people had to do. Really!! They read books, and learned that way!

That's how I learned, and many other on here learned. So, it's not impossible. But, it's also
not something that you learn and pick up in a few days/weeks.
There are a bunch of references on line. But, be
please careful! A
lot of the stuff on line is
wrong, incorrect, incomplete, does
not apply to your situation, and so on.
Finally:

Here are the forums where you'll likely learn more and get better, more informed help when dealing with an engine with a carb:
Classic Mustangs - Classic Tech at StangNet
2.3L Mustang - 2.3L (N/A & Turbo) Tech at StangNet
Good Luck!