*** Error Codes 43 & 54 *** How do it get rid of them ??

[Hole-Shot]

I am some error code issues. The main one is code 43 (Low voltage at electronic spark timing circuit). I replaced the module in the distributor, but I still get the code 43. I also get an occasional code 54 (Low voltage at fuel pump OR Low voltage at Fuel pump relay OR Output failure at quad driver module). This error code comes and goes. The car is a 1985 vette with a 1990 f-body (7730) ecm and a custom chip. I need some direction as to possible fixes for this. Thanks in advance for any help!