318 has developed a miss?

So I have a 318 that has about 25000 miles on it and runs good but I noticed the last few times I drove it seemed to have a miss and popped out the carb when I jump on it, only a few times. Now I noticed when in gear {automatic} stopped the alter gauge drops when the miss hit's. You can feel the miss and see it on the gauge.
Any thoughts on what would cause this or where to start?
Thanks