Is it desmogged or not? If Not and you are running original vac hoses have a good look there. No extra holes in the airbox? Double check the throttle cables and the enrichener acyuators and the position of the enrichener butter flys. My gut feeling is something in all the linkage either on the carb side or the enrichener side or both ain't quite copastetic. I know this is OUT there but you don't have a nitrous bottle in there you ain't aware of? Like i said-OUT there!

RIDE SAFE.