[StreetSnake]

I have a 427 W with a TWM stack EFI. When the car has been sitting, overnight lets say, I try to start it and it backfires through the throttle bodies. It does this once or twice and then fires up. When the engine is warm it doesn't do it.

I turn power on, wait for fuel pump to cycle, crack the throttle and fire. I don't have an IAC plate on the stacks and that is why I crack the throttle. Is it that or is it timing, I'm at a loss and so is the guy that tunes my car. Any thoughts?