So far nobody has mentioned the Throttle Position Sensor (TPS) adjustment. It does make a slight improvement IF it's spot on and the carbs are properly synchronized.
The factory manual describes it best, but is a bit confusing until you read it several times.
The overall resistance of the unit should be noted and then at full throttle with the engine off and the key on you adjust for 75% of the value noted in the earlier step.
I think there's a good write up copied from the factory manual -- it should be findable in the archives.