Scripley: A diagnosis of the FI system would show this, but ONLY if it is a complete one.

A defective cold start system ONLY shows itself in a cold start condition......it isn't even used when the engine is warm or hot.....this is controlled by the TTS. Hence your problem is something else..........something that is common to both cold and hot.

I would suspect the air by-pass screw adjustment is off. This is the large Allen head, knurled screw, located at the throttle plate area. Try turning it 1/2 turn one way, then the other........see if this helps. If not, then other tests would have to be performed.