Help!

I have a 1996 Nissan Altima. About a month ago it started blowing the fuse that controls the dash board monitors. (Speed, gas, oil light. Etc) Then my left head light blew. I replaced it with a new one and it stopped blowing the fuse for the dash board. Well, about 3 weeks later I got in it, started to crank it and it would turn over but would not start. Later that day I tried again and it started. As I was driving down the road the motor started trying to turn off. NOTE* it only does this when the motor warms up. Plus sometimes it will or will not crank. I have purchased and replaced the coil, coil wire and all fuses. Could you pleaseeeee tell me what you think the problem is? [/B]