Problem starting in cold

This is my first diesel a 2011 Jetta TDI Wagon. I know it doesn't like to start in the cold but for the past few weeks, as the temps get colder outside st. louis, it has been taken a few more seconds to start then usual. I just thought it was because the declining temperatures as it only delays starts in the mornings and then is fine for the rest of the day. Now in the middle of the afternoon when it is 20 degrees F it took about 8 seconds to start and then ran for about 5 secs and then died. I was able to start it right back up afterwards. I ruled out with the battery being newer not sure what else it could be. It also idled at about 1 RPM right afterwards where it usually sits a bit lower.

Any ideas?

Have you checked out this thread/sticky?

http://forums.tdiclub.com/showthread.php?t=302863

Also, are you waiting till the glow plug light goes out before your start your engine (ie turning the key half way, glow plug light goes out, and then turning it over)?

I'm in STL and have had a little rough idle on start up, the weather has been RIPE for an intercooler issue...

Something is definitely wrong with your car. Last winter, the temps went down to single digits here around Philadelphia. My car started up without issues all winter long. The intercooler issue is definitely a good place to start. Check for water in the lower hose.