I have recently recieve my brothers broncO. It's a 88 automatic wIth overdrive and is a 5.0 liter. It use to run goOd but has set for a few years and now I'm trying to fix it. It fires in all cylinders for like 5 seconds then starts missing. So I changed all the spark plugs, wires, distributor cap, and the button. Basically a tune up. I'm 17 and not really sure of what else To do because it still fires up great and then misses. You can drive it still but its just so rough I dont know what to do. Does anyone have any ideas or have had this hAppen to them.

 

And after it fires only 3 cylinders still are good. The other 5 do not