If the power feed wire to the distributor or coil is dropping out for a even a split second it's going to cause it to spark at the wrong time. Notice if you just turn the key on and off without starting on that type of ignition system it causes a spark. Maybe if that circuit has a problem it is throwing a spark at the wrong time.

Thanks for the reply, I have checked voltage it usually never drops below 10.5 at most and has gotten a new battery before. I thought about the amp draw too; it has new starter, ignition switch, and bat cables. I even added in a relay on the starter wire so it has direct power not going through all the safety switches. With no tank hooked up This thing cranks like crazy and sounds normal. This is a rental unit so I have had a lot of time with it. Have also gone through the timing a few times. Even got a new head from the possibility that it had been machined down to far and screwed up compression. Almost wondering if it's a controller issue, I don't see a ignition relay like they have on the gm 3.0s and there is not to many Mazda hysters running around

check the timing
and also check the volt drop on the battery and amp draw on the starter while cranking