Here's a unique problem with my 2004 S4 that has me perplexed. A little possibly related history:
- when I purchased it a few years back, I was surprised that I could start the car without the clutch engaged;
- shortly after I purchased it, I installed an automatic car starter - Compustar.

From about eight months ago until now, my car wouldn't turn over after sitting parked for longer than 8 hours or so. It seemed to be worse after long trips, which doesn't make any sense. Each time it wouldn't start, I assumed it was the battery. I'd charge it for 15 minutes or so and was then good to go. As long as the car wasn't idle, it was fine. I assumed it was a slow drain on the battery, even though there appeared to be plenty of battery with the lights and dash, etc. I even replaced the battery about a month ago and the problem persists.

This weekend, I left the car parked for about 72 hours. I put the charger on it just to check the status on Sunday morning and it was at about 70% or 12.2 volts or so. I didn't charge it and later checked and it showed 75%. I checked again this morning and the charge was still at 75%, but knowing that it wouldn't start, I charged it this morning.

When I went to start it later this morning after a few hours of trickle charging, the battery showed 100%. It wouldn't turn over. That's when it hit me: maybe it's actually not the battery. I disconnected the charger and waited about 10 minutes - the usual time that it normally takes on the charger before it would start. Once the ten minutes were up, the car started without a problem. The next time this happens (probably again today after work), I'm going to wait about 10 minutes after first turning the key to see if it will restart.

Does any of this make sense? Is there a process that happens when you first turn the key that starts a boot or preheat or system check that might be failing on my S4? Why would it work fine until it's parked for a significant amount of time? Could it be anything related to the fact that the clutch pedal check has been by-passed or the Compustar system? I've considered replacing the starter, but the starter does not hesitate at all once it's been given the green light. It's getting that green light that seems to be the challenge.

Thanks for any advice!

Dan