I found one reason its been rich, it was something to do with the coil location. I've been chasing this problem for over two years, bad idle, stalls, falls on its face, timing jumping around with wire disconnected, poor throttle response (stomp it to the floor and there's a 2 sec delay before acceleration) and a lot of other strange problems. The manifold is a Edelbrock performer EPS 2716 and I mounted the coil in the same factory location (behind the TBI) and never liked how it was so close to the distributor. So the other day I wrapped the coil with a piece of sheet rubber and it ran great, then I mounted the coil on the bracket that holds the MAP sensor and it's even better. I don't know what was going on with the coil but I'm glad those problems are gone and I can go into this tune as if it's a new build.