AutocraftCollision

We have a '79 280zx that needs new/rebuilt calipers, and the only one we haven't found yet is the rear left, which no one seems to have. Not on Ebay, at rock auto or Auto International or Autozone. Help me, borini63, you're my only hope!

the car is a 5 speed. when I say at idle, I mean not accelarating. like when shifting gears or coasting to a stop sign

When the engine warms up, the idle rises to 2100rpm. It stays there until coming to a nearly complete stop(~3mph), where it suddenly drops to 900. The car has no cruise or AC and has 62,000 miles. We brought it to our general mechanic, and he can't make heads or tails of it. Has anyone else had this problem before, or a good idea of what causes it?