2003 F250 6.0 runs rough, worse in high gear
 

New to group. I have read through posts similar to my issue and tried most of the suggestion, all with no relief. I'll try to be brief but include as much info as possible. Bought this truck 6 months ago, no problems until just recently, have put about 8K miles since purchase, has 158K total. On occasion when starting out first trip of the day, it would not shift and would be white smoke. When I let off pedal and pushed again it would shift and work normal. This happened maybe 2 out of 10 times. I would also intermittently get a red battery light. I checked batt voltage, 12.3 off, 14 when running, both batts. Then one day I was driving about 70 mph with cruise on, cruise quit, started running rough and couldn't go over 45mph. This lasted about 5 miles, eventually speed came back but now is running rough especially after it shifts into high gear at speeds from 45-70. Doesn't seem too bad at 35. Seems to run better with tow/haul on. Took it to Ford dealer and service manager was an absolute jerk so I left, they will never see me again. Starts ok even when below zero without being plugged in. At -20 it still started but took several tries. I took out EGR, pretty clean but cleaned anyway as well as inside intake, no fluid seen in inlet. I have done this twice. I checked voltage at FICM and get 48.1 at KO and 48.1 engine running. I checked this twice on different days. Had code for ICP sensor voltage. Replaced ICP sensor and pigtail, really didn't enjoy that. They were both oil soaked. In addition to the ICP change,I have changed oil and filter, replaced fuel filter and water separator filter and ran fuel injector cleaner in tank and driven 100+ miles . Where do I go next? After ICP replacement and run there was no change, same issue but had no codes after test drive.

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A little more information. By running rough, I mean it feels like a gas engine would feel if one cylinder wasn't firing, bad plug/wire, etc. You can see the steering wheel shaking as well as the outside mirrors. At no point is it running like it is supposed to. If I push the throttle up to 2000 rpm, in park, it does not remain stable. It will move up and down roughly 200-300 rpm's.