procharged 454

I am having proplem with my boat. Running at the lake of the ozark last weekend The motor would shut off and on while in gear put would keep running. If I shifted into neutal it would clear up and would rev , Back in gear it would sometimes pop and loose power only turn again . It always starts and runs until after a small cruse and to act up again. I replaced the coil in the water and it came out of it but the next day the proplem would return. I have checked for loose grounds and connection but everything seems tight. A freind suggested it the ignition module. I pulled it last night but now no can test because it is a 8 pin connection. Is there a way to test the module or is there something you think I am missing. No one at least at the lake has a replacement part and I would need to order one. Any thing am I missing or need to check other than the module.

Thank you

procharged 454

Still searching for issue, I replaced the ignition module and coil. Took it out yesterday did the same thing , Open the engine hatch look threw notes about 10 mins, tried it again started and drove great to the trailer. On a good note tested the BBlade prop increase top speed by 2mph.. Vapor locking?, pushed Accelerator pump and has gas. Fresh fuel added heat and sea form, Frustrated, look for possibles solutions..