97 Pontiac Grand am

About 4 months ago I started having trouble with my car. Never have I had a brake issue until now. I was driving down the highway, started to slow down but my brakes got so hard that I could barley slow down/stop. Then I felt the car start to shake(guess engine). Also it kind of back fires as I cut it off. Also it has a funny smell. Had my brakes checked out and they are good. Also had new spark plugs, and wires put in. Could some one please help me out. I'am on a very fixed income and dont know if it's worth fixing or just selling it as is. When the car starts to mess it up i cut it off and let it rest for about 10mins. After that I'am able to make it to my destination. Also it doesn't happens all the time. I may be able to drive for a week with no problems.

Was the vehicle stalling/dying? If yes, lost vacuum boost to the brakes.....

If it doesn't start right away, but does a little later, keep a can of carb cleaner in the car.....this won't fix it, but will confirm a problem.....if it dies and won't start, spray carb cleaner into the intake....if the vehicle now starts, and continues to run as long as you spray, and dies when you stop, you have a fuel problem......chances are you may have a fuel pump on it's way out......Easy to verify with a fuel pressure gage.....3.1's have a schraeder valve near the P/S pump....4 cylinders sometimes don't and you need to seperate the fuel line and install a gage with the correct fittings....