1988 Cruise Control

The cruise control has been acting up recently. I started to notice that the cruise would cancel by itself or it would just slow down gradually. I would press on the accelerator to get back up to speed and the cruise would hold there for a while then slow down again. Then it wouldn't work at all. But most recently it would accelerate beyond what it was set at. I had to hit the brakes at about 75 mph in a 50 mph zone to stop the acceleration. I was ready to start troubleshooting it and now it's back to working properly. Any ideas why it would have so many faults then go back to normal?

Probably the vacuum module getting ready to retire.

Sometimes the valves in the vaccuum control assembly get dirty.. but the computer controls those and usually compensates..

I had trouble with mine cleaned those valves and had to replace the Computer. That was AN INSTANT FIX. Junkyard Computer. C H E A P.

I have very similar problems with the cruise on my 91PA. Where do I find this "vaccuum control assembly" that I can clean??