Electrical issue

Hello, I have an electrical issue on a 2011 Navistar propane bobtail. Almost impossible to replicate, seem to take 10+hrs of run time for the issue to show up. I've spent hrs making sure all grounds were good. Cleaned all associated relays I could think of and still no dice. I have a video of what's happening, not sure how to post it. Basically every warning light in the dash is flashing and there is a noticeable cut out and cut in of the engine about every 1 to 2 seconds. Any ideas would be greatly appreciated. Thanks, Mike