Engine 88 5.0 gt stalling

[Jleach]

88 5.0 stang 30 lb injectors has gt40p heads, performer cam and upper and lower intake elbrock rpm 2, cold air intake, 78 mm throttle body ,msd 6a, msd coil shorty headers to h pipe to flowmasters 3inch exhaust all the way , 5 speed
Runs decent but when I go do down shift it wants to stall any as soon as I push in the clutch she just drops off. Help please

 

[Blown88GT]

When it was converted to MAF, the PO didn't connect the 2 extra wires from the VSS (if it had one) to the EEC connector.
VSS = Vehicle Speed Sensor
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