So I recently purchased a 2000 F250 super duty 7.3 power stroke with 246k. I actually traded my 96 wrangler, 02 ram 2500 and a car hauling trailer for it. I now have one vehicle and it’s not running the way it should. So the first time this happened, the same day that we made the trade, I ran it through the car wash and all of a sudden about a quarter mile later it started losing power and falling on his face. Eventually got it back home and the only codes it was showing for a P 1000 and a P603. I turned it back to stock and it still wouldn’t run very well and had less and less power. Three days later I was waking up Monday morning to take it to a diesel mechanic and it acted as if it had never been symptomatic and it ran absolutely perfect. I took it anyway. The guy ran a few scans and told me I had a great truck so I left. Four days later on Thursday, I was driving to an appointment in the rain and about 10 miles into my drive it started doing The same exact thing. I drove at the rest of the way and then drove it the other 17 miles back home. It’s been three days now and I’ve been looking for anything I can, harnesses are tight, I pulled the PCM and IDM out of the fender wheel well and inspected for water, cleaned them and coded them with dielectric grease and still nothing. I took the cps out and inspected it, fine. I took it out again and it started throwing a code saying exhaust back pressure sensor low, I can’t remember the exact number. But it feels like there’s a miss, and when I get it up to about 40 mph and let off the Excelerator, all of a sudden the service engine light will come on momentarily and then go back off. It only does that when you can feel the back pressure from the exhaust deceleration. I don’t have another vehicle to drive and I’m literally lost as to what to do now. before we made the trade, the guy had new pigtails put on the harnesses at the Ford dealership. It also has doorman head gaskets, so I know that is not the problem as well. There are a lot of new things that have been replaced on this truck, it’s a long list, and I’m fairly certain it’s something electrical, but I just cannot seem to find it. I also have a leak in my roof that drips out of the overhead display, but I don’t see that being a problem unless someone else knows some thing I don’t. Please anyone, I need some help!