rebuilding/repairing your AFM

I'm pretty sure my resistance track on my airflow meter (78 280Z) is totally worn out, or just really worn. The resistance with the flap closed isn't (near-zero) like the book says, and it doesn't go up smoothly with movement of the flap. I could order a used one, but then I'd have two, so why not have a go at fixing the resistance trip? I think I'd probably need to graft one from another source, like a giant potentiometer or another similar AFM. Or is there a source of material used to make resistance strips?

thx