I've been having this trouble for a few months now. My '01 A4 will crank all right but usually will not start in the morning, or after sitting for awhile, but will then start after 2 or 3 attempts. The good news is that it has always started, just hardly ever on the first try. I have searched for threads with this issue, but could not find this particular situation of an engine that won't start, then starts after multiple attempts.

I am getting the following engine codes:
16795 secondary air injection system incorrect flow P0411
17963 charge pressure maximum limit exceeded P1555

Another issue I am having is with my secondary air pump. It sounds like a "jet engine" on startup, as I've seen it described in some threads. This lasts for approximately 30 seconds. The noise started the day after I hit a raccoon on the right front of my car, so I suspect cracked hoses or something? I'm not as concerned about this problem at the moment.

Does anyone have any idea what could be causing the startup issues? If I can provide any more info, please let me know. And any help would be appreciated.

Thanks