I've seen a couple of other threads on similar issues - involving the starter / EPC light on these cars.

A couple of times over the last six months or so when starting the car there has been a pause of a few - perhaps 3 or 4 seconds - between engaging the start position and the car turning over. Once, about a month ago the EPC light came on after the engine started. I turned off the ignition, removed and reinserted the key, and the car started properly.

Today I returned from work (about a 30 mile commute) and went back out after a half hour or so to run a couple of errands around town. I went into the grocery store and when I came out 15 minutes later and attempted to start the car all I would get is a faint "click" that sounded like the starter attempting to turn over - then the EPC light would come on. Tried several times, same thing. Finally I disconnected the battery for about 30 seconds, reconnected it, and tried again. The first couple of times nothing happened, and then on the third or fourth time it started normally. I drove it home and tried starting several more times - no problem.

VAG-COM shows the following

19510 - Starter Will Not Turn - Intermittent
P3054 Jammed or Electrical Malfunction

Is this likely to be the starter itself, or some computer gremlin / sensor issue?

 

Start with the simplest thing first. It's probably the starter. The click you hear is the solenoid engaging but the starter motor is not turning over. Most of the time it's the high current (high amps) contacts in the solenoid not making good contact and therefore not passing enough juice to turn the motor over. I'd pull the starter and have it tested and go from there.