'95 530 Criuse Control
 

When engaged, cruise control does not hold set speed; speed slowly "decays" but not as quickly as it would if cruise was simply disengaged. Local garage suspects cruise control module. Any other suspects to eliminate before replacing module?

maybe you have some kind of crack or something in a hose in ur vaccum system

I agree with "perf", it's a vac leak. If it was module or electronics it wouldn't engage.