As others have said Sounds like the Box is failing. I had the edge comp on my 99 for 10 years and it started doing odd things. I contacted edge and they sent me a replacement Comp for nothing. I was and am a very loyal fan of the edge comp. Then my VP 44 died. And I was not in a position to replace it my self. I took the truck to a local diesel performance shop and I specified I wanted the high end blue chip replacement VP44. When I returned from out of town to pick up the truck the shop told me that he was not going to reinstall the Edge Comp but instead sold me a smarty. I was not happy about this but the shop said if you do not like the smarty to bring it back and he would hook up the Comp. so I decided to give it a try. Having towed from Alaska to FLA and back three times at 18K Total weight while using the Comp I was well versed in the Performance of the comp. I left Alaska towing my fifth wheel at 18K to go to FLA the smarty was by no means even close to the comparison of the COMP. But I did not have to constantly watch my EGTs using the smarty. The Smarty did increase the Power and it came on differently than the Comp. I decided to just leave the Smarty and not to go back to the Comp. I left the 99CTD and My fifth wheel in FLA and I now fly in and out. I just finished a truck only trip from FLA to MD and back and I use the truck when I am in FLA as my primary vehicle. I have a friend plug in the block heater a day before I get there, Then I reconnect the batteries and she starts every time first turn of the Key. There are Moments when I miss the seat of the pants thrill of the COMP on 5X5 and I have considered stacking, but I just don't have the balls to do it. I like the blue Chip pump I like the Smarty I like the reliability that I have under the present configuration. So I do not think I will Stack the Smarty and the Edge Comp. I am pleased overall with the Smarty. Hope this helps.
Chris