HELP

i have a beautiful 2005 X Fire, I’ve had so many issues with it, I’ve replaced the convertible top, alternator, battery, Crank shaft censor, cam shaft sensor, I soldered the Film of black substance that was on my Fuse connections, my car runs fine for about 20 minutes then stalls out every time I come to a stop, it will start right back up INSTANTLY and when I give it gas the front of the car will shake terribly, but it will not PULL I drove it under 45 and whenever it hits 50+ it’s happens, when I come to a stop it dies out and my battery light in the dash pops on like the alternator is bad or the battery isn’t being charged. So I turn the key off and turn it right back over and it’ll take right off. What’s causing the car to not pull!! The transmission doesn’t seem to be bad at all. I shift from drive to reverse and 1-2-3-4 smoothly. It’s just when driving and shifting, or when I come to a stop, it’ll idle at 100 RPM’s and then slightly increase to 3-400 and then back down 100 and die out. PLEASE HELP IVE OUT 6,000 In my car form a top, to all the side fixes. I really love it and would love to see it run again. TIA!