Mass Flo / Ford Mustang F.I. help needed

[Ronbo]

That's true. But you could end up with lean levels being detected by the O2 sensors or unusually high air flow levels reported by the mass-air meter (or high air flow not being reported in the case of a leak). I'll have to check, but i believe the SPOUT also diables most of the other logic loops besides timing adjustment. (basically the computer only uses the fuel map)

Vacuum leaks are one area that the computer's logic processes can't compensate for very well.

The Mass-flo system has a "bare bones" set of sensors, especiallly compaired to today's setups so it's not as forgiving as the sales fluff makes it sound like. For example no speed sensor or knock sensors like most modern production systems.

Actually your post threw up a flag, coolant leak? An intake gasket could be your air leak as well.