runs with a miss when u first start it and then dies after about 1 minute

[josh]

I have a 1979 rx7 and some times it will start and run real good for 5 to 10 minutes before it starts running with a miss and dies and other times it will run for a 1 minute missing the whole time before it just dies but if it starts to die and you start pumping the hell out of the gas in time you can keep it running it just misses like crazy any kind of an answer would be nice I'm going to take the carb of and have it rebuild for starters and go from there, but im not sure that is it it sound like its some thing in the firing system I thank but don't know I'm a mechanic by trade but this is the first import I've owned or worked on so I'm kind of lost for the moment.