dead in 4 audis i've had

mY SPEEDO PROBLEM (INTERMITTENT NOW)...
 

Sorry, didn't mean to shout...
When the speedo is functiopning correctly the cruise works just fine. When the needle begins to bounce the cruise control disconnects just like touching the brake pedal.

I'm going to try and remove the capacitors in the speedo and replace them. I'll bet they have cooked under that black dash. FYI - electrolytic capacitors dry up and eventually fail altogether. Since my problem appears to be temperature related as well I'm betting this is the issue, or a wire in the mechanical part has cracked and makes contact when it warms up. Still shooting the trouble.... more to come...

both. check for vacuum leaks, such as at the pedals, or at the servo.