I have a 1987 R10 305 TBI. It keeps losing spark. power to ignition button. If i plug a spark plug into the coil wire it sparks, when plug into distributor no spark. so we double checked voltage and has voltage even when not firing. Distributor has clean post and we installed new rotor button. If we get spark and it starts after cranking it for awhile it miss fires like crazy until it finally stalls out and dies, then when we try to start it again, there is no longer any spark. We have tested everything that we could look up. Do not know what else it could be. Also there is proper mist from the injectors and pump works. Even went through the trouble and changed the timing chain and sprockets out just to be sure and it was in time. So any advice to the problems would be awesome. Do not know what else we could do, besides start spending a lot of money to find out its a simple issue.