Wierd decel issues, Help Please.

[03Sierraslt]

I am getting a wierd lean decel, however its not under all decel. I am 2barOLSD, the lean spot seems to occur between 35-25kpa then if below 25kpa it goes back rich. I dont know why this is happening, at the end of last season when I parked it I was getting a rich decel, but no lean spots like this. At first I thought was only happening at a IPW of 1.6 but I see numerous spots where it hits a IPW of 1.5 and doesnt do it.. I am lost here. Can someone please look this over? Thanks

[03Sierraslt]

Basically the only changes between the end of last season and now are the built trans and PI 2800 stall.

[03Sierraslt]

Anyone? Something is not right, but I am not sure what. It wants more fuel at 30kpa then it does at 40kpa?

[03Sierraslt]

No one has seen anything like this?

[03Sierraslt]

?????