no spark

I have a 91 Mazda 2600 pickup with 46000 miles.. It died while driving, then started again and ran 15 minutes, died again and ran for a little while. Finally it could not start any more. I discovered I had no spark. I replaced the coil, wires, plugs, cap and rotor. and still I have no spark even at the coil. I don't see any fuses blown. I don,t mind replacing parts as labor costs are about $75.00 an hour, plus I would have to pay a hundred something to have it towed to nearest shop. Are there relays or hidden fuses? Something in the distributor maybe? Haynes manual does'nt seem to be very helpfull at troubleshooting.