I had this problem on my drivers door...and am not 100 % sure on how I solved it..(it was 13 yrs ago), but there was a flat piece on the mechanism that the rod in the door handle pressed against...and I bent it slightly towards the rod...worked fine after...think it had bent slightly after 40 yrs...could be similar w a too short rod...you may be able to add a piece , shim the flat part....?