Cummins 8.3 Caps issue

I have a 2003 Peterbilt with a Cummins 8.3 ISC with the caps pump. I have been having issues with the truck, first problem was a break down, i scanned it out and did some testing to determine the stator on the caps pump failed, I replaced it along with the transient suppressor and the truck fired up and ran great for a couple months. The next issue was it went into power derate due to the rear pumping element, during this the engine light came on and stayed on, i diagnosed it and determined it was the rear pressure valve on top on the caps pump accumulator. Replaced this and it has been running well ever since, except the engine light comes on at times during load (certain accelerations), only for approx 2 seconds and goes off again, when the light comes on, it detrates power for a second but the power comes back when the light goes off. Once the truck warms up the engine stays off. I am getting code 329 sid 233 fmi 7. I have checked all the basic things like replacing the fuel filter, both fuel lines are new. In planing on selling the truck and can not get this problem to go away, any help would be appreciated.