Alright, just as the title explains. I parked the car for a moment, shut the engine off, and once I got back in the car won't turn over again. I noticed that the gauges seemed to be vibrate upon initial start up, if that has anything to do with it. The battery has a charge, so that's not it.

If I hold the key to start, it seems to repeatedly try to "fire" the ignition (the interior lights dim) but nothing turns over.

Any ideas to begin trouble shooting?

 

Check for fuel pressure, check for spark like stated above. I would also check the charging system once you find your no start problem. Checking relays or checking the fuel pump. At ingntion on not start postion do you hear the fuel pump come on. I know my s-type is loud. You will hear a hum or a sound like something energizing if you get the idea. This should give a go at what you need to check or put you in the right direction. Good luck.