1979 2.3L Mustang

could be that the float level is set too high (or stuck float) and is flooding the intake manifold with fuel causing it to run fine for a few minutes and then flood out - giving the bucking you describe.

I was kinda having a similar problem with my 81 sans the mistyness and carb exhaust. Although I think mine also needs another oil change.

I had this problem with my '85 2.3. Make sure the screws between the throttle plate and air horn are tight. They are famous for vibrating loose.

Take off your air cleaner and grab the carb with your hand tightly then try to move it. If the carb has play, 90% of the time its the base plate being loose from the air horn. Major vacuum leak!!! I used LOCTITE thread-locker on the screws and the problem never came back.

While the carb is off and you are tightening the throttle plate screws (torx), make sure all the screws all over the carb are good and tight. These carbs are known for vibrating loose.

Also if you are having problems restarting the engine after a long drive, in the summer, you need a phenolic spacer between the carb and manifold to displace heat and some high-temp insulation on your fuel line from the fuel pump to the carb.

I hope this helps...