Or the past two months, occasionally when I would go to start my truck it would crank for a really long time ( about a min) then start. It only did it about in two months. Then last week, it would not

 

Start at all, I took it apart and found it was getting no spark and the coil wire was really corroded. So I thought it would be a good excuse to do the six liter tune up. So I did the tune up and it started. It ran great for the next two days and then it started to crank for a longtime again. Today it will not start at all and I had to get towed home by a dodge. Please help me
My truck 1996 f150 4.9l 5speed