SC Idle Problem
 

Looking for help with idle problem. After starting cold, the idle ocillates from 0 to 2000. After it warms up by applying the throttle to steady the idle for a minute or so it will idle at 900. The first few miles driven thereafter it tends to stall when decelerating. This problem happens at about 3000' elevation at 55 degrees. At sea level at 70 degrees it starts and idles normal. I just purchased this car so I'm new to the CIS system. and am hoping someone can narrow down the seemingly many possible problems.

You should get your mixture set using an exhaust gas analyzer. See if you have the same symptoms. I'm guessing you're running a little rich, which will only get richer as you go up in altitude.

Welcome to the brotherhood of SC ownership, 80Targa!

Bill Krause has already posted a suggestion for you, and if you want to master the Confounded Injection System (C.I.S.), I'd suggest reading Probst's book on Bosch Fuel Injection. Our host (Pelican Parts) can get it for you.