38-40 psi is the stock and recommended setting. If you drop it to 32 the engine will lean out for a short time. Then the computer will simply widen the pulse width of the injectors so the proper air/fuel ratio is met.
So basically set it at 38 psi with the engine running and the vacuum hose disconnected. Removing the hose simulates wide open throttle.
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1988 Mustang GT
11.8 @ 123 (7/14/01)
11.5 @ 120 (9/14/01)
1992 BadAzz Wrangler
1993 Explorer
See my car at:
www.mustangworks.com/cgi-bin/moi-display.cgi?179