1979 spider veloce. Starts great. Idles great (~600rpm). Step on gas ... stalls. Will restart (sometimes needs a couple extra seconds). I can tap at the gas pedal a couple times and it gets going. At speed runs like a top. Hot, cold, whatever, it always stalls when you step on the gas while idling. No warning lights (and I have seen the fuel pressure light come on for a split second at start up so its working.) Other than new fuel filter, any clues?