So after landing and leaning the mixture for taxi I came to a stop and went through the shutdown checklist and I find that I can't move the mixture control at all. It is completely stuck. Somehow I was able to muscle it enough to idle cutoff but currently I'm grounded for the night in KBGE with a mixture control that won't budge an inch either rich or lean (it ended up being stuck exactly in the middle of it's travel) . Has anybody had this issue before? I have a 1976 M20F. I haven't had any signs of the mixture control being tough at all, it worked like a champ the entire flight and even leaning after landing. One thing we have ruled out is that the servo is not the issue, the lever moves fine, so it must be somewhere within the cable. Is it possible a cable could have seized up? Anyway, I'm stuck here until I can get home.