It doesn't really seem like a fuel starvation problem, (perhaps an air overabundance problem?
) because after the initial throttle tip-in, so long as it doesn't stall, and after it hesitates, it'll take off and accelerate just fine. If you've ever driven away after a cold start, in a carbureted car without a functional choke, this is EXACTLY how it feels.
Again, this ONLY happens right after a cold-start, it doesn't have to be cold outside for this to happen, (although that exaggerates it) just after the car has sat for several hours and has cooled down completely.
A little background on the car:
Following the advice of a "Mercedes mechanic", (he said he used them all the time, with great success, to replace the crappy stock coils in these cars) I put an MSD Blaster ignition coil on the car about 2 years ago. The old coil was bad and caused the car to miss intermittently at idle and during acceleration, after being warmed up. The coil solved the problem and the engine had been running great since then. The plugs are less than two years old, with about 15k miles on them. Cap, rotor and plug wires were all replaced about 3 1/2 years ago.
In the past three years, pretty much the entire fuel system on this car has been gone through. The fuel distributor was replaced with a rebuilt BOSCH unit 6 months ago, the fuel pump and filter was replaced about a year ago, and the fuel accumulator and regulator about 3 years ago. It had been running quite well with all that work being done.
I'm wondering.. The last time I had the airflow meter off, (months before this started happening) I noticed that the idle air hose coming off the bottom of it was a little on the hard side and kind of loose around the fitting. However, it had been running fine now for months since I noticed that. Would a small air leak from that, possibly cause it to be running a bit too lean (beyond the correction ability of the EHA) after a cold start, but not noticeable after being warmed up? I don't think that I'm going to get any meaningful DC or current readings, as the system is running in open loop at that point.
Remember, it starts up and idles fine, after the cold start. It's just when I try and take off from a stop or hit the gas at a very low speed, for the first minute or so afterwards, that it stumbles, hesitates and wants to die. After the engine warms up, or after a successive (warm or hot) start, no problems.
Any other ideas?