It's been a long time, but is there a cam adjustment that can be turned on the no-op side of the fuser to increase the spacing between the fuser rollers slightly?
Is the fuser in good condition, or does it possibly have a swelling on one side of one of the rollers? Sometimes near the end of a fuser's life I've seen the rollers develop oddities that can cause odd issues for the last 1,000 sheets.