Working on a rig for a buddy of mine, 7.3 with auto trans, bone stock except the straight pipe. No check engine light. It was running low on power and would randomly shut off. We changed the fuel filter, fixed the low power issue but it still randomly shuts off. He got some idea in his head it was the cam position sensor and changed it, now it barely starts (when it does at all) and when it does it has a huge lope, like a 500 rpm swing. I'm stumped, anyone have any ideas?