New answers tagged saab
Possibly a problem with the computer that controls them (which might be the BCM - Body Control Module, or might be a separate dedicated module). A friend of mine had the same problem with a 2001 BMW, and water had got into said module through a perished seal and shorted a number of connections within it, causing the lights to go on and off at seemingly ...
From your description, I doubt anything you've stated is at fault. I would bet the vacuum port you used for testing is associated with another device which is where you heard the "ticking" sound. As this alternate device is turned on/off, it is causing the wild vacuum readings you are seeing. If I were to guess, I would think you are probably reading ...
That is a leaking intake valve. The needle swing coupled with the "tic" sound are classic symptoms. Off comes the head. After repair of the engine problem clear the codes and see if the CAT fail code resets. Poor combustions can fool the catalyst test. source: 30 years automotive diagnostics.
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