The vacuum was always an issue as far as somewhat low, and erratic. When I first got the car the idle was set at like 1100rpm. I only drove the car 2 or 3 times last year.... so to be honest I really didn't take any notice of it then.
My thoughts as the they kept the high idle to keep it running smooth. Does the problem get be better just off idle? Meaning, does it smooth out if you raise it off idle?
