ISX cm2250 emissions help needed

[dslmchnc]

I have a 2012 389 peterbilt with a 485 isx cm2250 cummins. This truck has been an albatross from the day we bought it at the beginning of this year. We purchased it used and it had scr fault codes in it after only one day of running. We eventually found that the scr unit itself had split the case from having a broken hold down strap. The catalyst was full of dirt and debris and needed to be repaired. There is a machine shop locally that does all of our dpf cleaning for us and was able to clean it and repair it. after that was all said and done, we ran the truck without issue for about 3 months. Somewhere between then and about 2 months ago the truck started using coolant pretty heavily. The driver never notified us of this issue and kept adding coolant himself. we finally caught wind of it and check the egr cooler, upon removal of the outlet hose we found that the cooler had ruptured. We replaced the cooler and the coolant loss ended. About two weeks ago now the truck was in a derate and had dpf differential pressure fault codes, i believe 3583 was the code. i checked the tubes for blockage and correct orientation, found that ok. I observed that the outlet dpf sensing port on the differential pressure sensor had moisture in it and the sensor itself had wtaer in it. I replaced the sensor, made sure the tubes we clear and ran a parked regen. The truck passed the regen and seemed ok. I sent it out for a test drive and as soon as my driver got 10 mins into it the regen required light came on. the truck returned and i found the retun voltage from the differential pressure sensor was below cummins specification. i watched the data while i wiggled the plug and found the data erratic during movement. i replace the shell of the connector and thesilicone boots, along with the pins. I initiated another parked regen and it passed. Again i sent the truck for a test drive and agin smae dpf regen request light came on. this time when the truck returned i had fault coded 3375 and 3376. i ran anothe rparked regen and ran a restriction test which the truck failed. I removed the doc and dpf to have them cleaned. both items passed the flow test that they perform after a stage 2 cleaning. i reinstalled both items and reset the dpf and ran it through a parked regen. same problem after test drive, 3376 and 3375. The dpf again faled the on truck restriction test. I disconnected the exhaust outlet and ran a snap test and found no smoke exiting the engine. i replaced the dpf with a cummins reman. i also removed the hydrocarbon doser and cleaned that, along with cleaning the imap sensor, cleaning the egr differential ports and sensor, the exhaust back pressure sensor, and even replaced the exhaust pressure sensor when i noticed that in a KOEO condition the barometric reading, which is an absolute pressure sensor as well as the exhaust back pressure sensor, dissagreed on preessure. I reset the dpf again, and sent the truck into service. the truck got about 2 hours into its run and the regen light came on. The driver pulled over and initiated a parked regen. We sent another truck up to it to take its trailer, and brought the truck to cummins because it was only 10 mins down the road. they looked at it and determined that the hydrocarbon doser was malfunctioning and replaced it. we took the truck back, picked up a new trailer, loaded the trailer, and got about 4 hours total use before the regen light came back on. the driver initiated another parked regen and was able to get it back to the yard. it snowed here saturday and now im tired from plowing and chasing our sanders around all weekend, and am at a wits end. I need help. one thing that i notived that seemed strange was that the exhaust gas pressure during the parked regen was about 163 inhg during a parked regen. it seemed high to me. this truck has 215xxx miles and over 10600 hours, i realize that is a lot. we have a 2016 t700 kw with 8500 hours and 250xxx miles. please reply with any advice, any help is appreciated. DSLMCHNC