Power fluctuations

[madmanmanick]

I have a 1993 Dodge Ram D250. I am having power fluctuations. I have replaced the battery, alternator, installed a ground wire between the engine and the frame, replaced the wire between the alternator and the ground. The previous owner it looks did some modifications to the wiring harness and installed a separate voltage regulator and looks possibly bypassed the PCM. Do any of you have any suggestions on 1. What might I try to fix this. 2. Where I can find a new harness( I have only seen them on eBay, but those are all used). Or 3. Do you think replacing the PCM might fix it, or do I have to replace the PCM and wiring harness?

 

[EDankievitch]

You sure your grid an fuel heaters are not cycling?