Cold start, is misfiring normal?

I did do a search, but there seem to be a buch of issues related to cold starts, and I'm really at this point just wondering if a little rough idling is even close to normal, or if I should get the car checked out.

I'm a newb, so maybe it's not corect to compare the symptom to a gas engine, but here's what I notice:

2003 manual, 80+K miles.

Temps are getting into the 20's and the glow plug light is staying on for maybe 5 or 6 seconds, so that seems normal. I start without touching the accelerator and it starts right up. BUT - the idle is rough, and it seems exactly like in a gasser where one or 2 cylinders are not firing. After about 10 seconds the idle smooths out and it runs fine.

The glow plugs and harness are new, and someone with vag-com checked the timing when I bought it and that looked good.

I'm just wondering if this will get worse when temps get lower.

Any thoughts?

Thanks!

Normal.

You should hear it at around 0*F

One thing is try two glows.
If your mechanical timing is set "correctly" you can experience this. Many (myself included) have our timing set to the upper 1/4 of the timing range rather than right in the middle or "correct" setting. For some reason just advancing the timing slightly seems to make all the difference for some cars.
The chug you are having won't hurt anything though. And yes when it's super duper cold you might get a vroom vroom vroom as the engine tries to keeps itself at idle until it warms a little. You could start it and then increase the idle to 1,500 or 2,000 for 30 sec or so to help it with the misfire. Up to you.

I've read about turning off the key and waiting again for the glow plug light, but does that really make the glow plugs hotter? Seems to me that they would be thermostatically controled - like they get to a certain temp and the light goes out - turn them on again and they just get to the same temp, only faster.

So, is what's happening just like in a gasser where the fuel mixture in one or 2 cylinders isn't burning? Does a new TDI do this? I ask because 100K miles on these engines is supposedly no big deal, whereas on a gasser, you might expect a 'tired' engine to misfire when cold.

fret not, it's completely normal. my '04 with nearly 40K miles does it, when it's in the upper 20s overnight. my '97 with 315k miles did, then i sold it to a lucky guy in TX and i hope it's still doing it and working for him. So in other words, relax and enjoy the big truck sound and feel for a few seconds, not to mention the diesel fumes. Once i got my mufflerectomy done it started sounding like a big truck too; i do miss trucking...

multi cycling gets the air in the cylinder hotter. There's no thermostat to limit the temperature.

The reason it is 'missing' is that one or two cylinders are not hot enough yet for the fuel to burn. After a few more revolutions the heat from compression will warm the cylinder up sufficiently for combustion. You can hasten this by multi cycling or keeping the RPMs up until it evens out.