16V - hard start

[Prime16]

I've described this problem on other forums and gotten nowhere, so I'll try to be very thorough.

Last winter the car started fine. In springtime, once it got warm enough outside that the cold start valve wasn't engaging, it was taking a little more cranking before it would fire up when the engine was cold. If it had been run recently, it would fire right up. The problem seemed to worsen gradually over the warm months, and I was hoping it would go away once the weather was cold again - helping me to diagnose. Cold weather came again and things did change, but not as I expected. Now the cold start valve engages, the engine fires right away, but will not keep running unless I hold the key in the start position as it fires, quits, keeps cranking, then finally fires and settles in. This whole process takes about 5 seconds, sometimes longer. After it starts, the car runs perfectly.

I'm thinking that the car is losing fuel pressure as it sits. The cold start valve hits it with enough fuel to get it going briefly, but there's nothing in the lines to follow it up.

Virtually every component of the fuel system has been replaced in the last 3-4 years, fighting emissions problems that turned out to be the cat (long story - too painful to tell). So it's got fairly new fuel injectors, EHA, fuel pump, fuel filter, fuel accumulator, fuel pump relay. The car has been tuned up and is getting good spark.

I'm leaning toward the fuel accumulator, even though it's not that old. Anything else I should look at before putting my money down?

In other forums I've been told that it's the cold start valve, but I don't buy that since the problem persists even in warm weather when the cold start valve is not in the loop. I've also been told it's a sensor that engages the cold start valve. Again, this doesn't make sense, given the symptoms.

Sensible suggestions appreciated!