Could be fuel accumulator valve. The function of this check valve is to maintain fuel pressure after shutdown. Is it worse in the morning at first start up?

The valve is located back with the fuel pumps. Costs about $90. Easy to replace.

My symptoms were that on overnight startup I had to let it crank until the fuel pressure built up enough for the engine to start. Since the valve had a slow leak, start ups after short shutdowns displayed less of the fuel starvation syndrome.

Steve