Well, in 35 years of getting greasy, I have never seen a vacuum line that fixes itself, simply by having the power to the engine turned off and on....
I figure there are probably some things that ford can extract, which other machines simply cannot access, although I don't think the 93 computers have all that much intelligence anyway. I am sure that the OBDII versions hide a lot of things to force us into the dealer, but I'm a cynic when it comes to that anyway..
John