CIS problem solved
 

Just thought I'd share my experience with you...

Intermittent problem (the worst kind). Sometimes about 40 seconds after startup, the car would really begin stubling at idle very badly - like it was running on three or four cyls. Sometimes it would be driving fine, and then start missing badly. Took it in to European Performance in Cameron Park, and Marc Hoover nailed it - bad lambda relay. Excellent diagnostics, and the relay was only $25. Car runs like a champ again.

I'm a happy camper!

Damn! I was hoping to get a potential fix for my problem but alas I dont have a lambda sensor on my '77 930. Glad to hear you found it though, enjoy.

Glad to hear of your cheap fix Mike.

Thanks for posting the solution too, it helps all of us that are trying to fix those annoying problems with the CIS.

And another CIS problem bites the dust. Glad to hear the happy news.

pretty common problem. the DME relay should be replaced too, if it's old.

JW:
Can you explain the function of the DME relay, and where it's located ('80 SC)? Are there any other electrical components that do not age well, and could leave you stranded?