Here are a couple of photos of the CIS Gauge - and a couple of the tests being plumbed up. If the +12 volts supplied to the interior heater element is missing on your car the resulting fuel pressure regulation will not be correct and can produce all kinds of idle and run symptoms.
About half way down the page is a photo of the gauge set up -
FUEL INJECTION TESTER FOR CIS-K-JETRONIC BOSCH SYSTEMS - Page 2 - Rennlist Discussion Forums
This is a description of the WUR test procedure -
Pelican Technical Article: Testing Bosch CIS
Here is a Utube procedure for running a CIS pressure ops check -
https://www.youtube.com/watch?v=h7drhxjJ2mg
Michael