96 E320 Starting Problem

I've posted about my problem before, and I still have the same issues about starting, but now I have established a pattern. My car starts fine in the morning, but almost like clockwork, when I go to start it after work, or at lunch, it cranks but no start. May take about 10 tries, then it just seems like it catches and starts up. After that, if I start and stop it, no problem. Starts the next morning, and the process begins again. My shop I go to had a known working fuel pressure regulator that he replace for me, and no difference. I have replaced almost everything that I can think of except the fuel pump itself. I hear it engage when I first turn the key in the morning. One thing I do notice is that when I am cranking the car, if at first I step on the pedal and keep it depressed, it helps out and the car starts.