I never seen a bicycle or motor cycle cable that was a precision push pull type.
Add to that, the inner liner of the Impala outer sheath is nearly always compromised and part of the problem.
If you come up dry with a correct application part I would suggest contacting a cable manufacturer that makes push pull control cables.
custom morse control cable
They will typically be threaded housing and 10/32 cable ends so there would be custom work to be done.
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