Cranky ALH when cold

So this is my first winter to own a TDI. Here is west Tx the winter is starting to come and like every diesel engine this one doesn't enjoy it quite so much. It still starts fine it just takes a extra second or so to fire but once it fires and is driven it starts right up provided its still kinda warm. Last weekend I replaced the o-ring on the IP head and it ran way better. Since then the cold has hit and it is doing the common idle stumble when slowing down, at a stop light etc. It would do this rarely when it was warmer outside but it is practically stumbling all over itself when its below 35 deg or so outside. Once you accelerate it runs like a champ and cruises just fine. With this the fuel mileage has dropped which I know happens to any engine during the cold from winter blend fuel etc. I have been reading the thermostat problems that are common but I put a brand new thermostat in it about a month ago but it very well could be keeping the motor too cold. I don't know what the pop open temp on it is but it was a quality kit from ID parts. It could very well be I got a hold of a bad tank of diesel and I have put some additive in it to help but I haven't noticed much improvement thus far. I dont have access to VCDS so I know it may be hard to diagnose timing issues. I will check other common things like the ASV and vacuum lines this weekend. Any ideas will be greatly appreciated. 02 Beetle ALH 5spd with 274K. Thanks

Timing and Injection Quantity calibration comes to mind. But both require VCDS.

Yeah I figured that might be an issue. Wish there was someone close by that I could bum VCDS off of. Just cant bring myself to spend the money on it yet.

That's smart, you only need it for specific operations, but it's darn handy for diagnostics.
No replacement for sound mechanical knowledge.
Try any local groups with Audi/VW members, you'll find someone.

My '03 Golf started a lot better after I tapped the IP case pressure relief valve back in. It had obviously walked out a bit at 130,000 miles.

^^^ I would check the case Pressure Relief Valve if I were you, it can cause improper timing advance negatively affecting your fuel economy and power as well.

And, the procedure for checking it is exactly what?
This may be the problem I am having on my car as well.
Thank you.

Prairieview said:

And, the procedure for checking it is exactly what?
This may be the problem I am having on my car as well.
Thank you.

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Simple as it sounds, unscrew it from the case, take a close look, it's most likely walked out a bit, tap it back in, re-install. Find some photos if needed.

Love that custom TDI search!
http://forums.tdiclub.com/showthread.php?t=238872

Thanks Bob. My search did not yield these results. I will go through this.
Sorry to the original poster to ask in his thread....although, I thought the info received might help him as well.

(I am a bit familiar with these valves from the earlier 1.6's...even have one here in the house from years ago. Although, I personally never had a problem with one in the old cars in almost 39 years of running them. Believe it or not.)

Prairieview said:

Thanks Bob. My search did not yield these results. I will go through this.
Sorry to the original poster to ask in his thread....although, I thought the info received might help him as well.

(I am a bit familiar with these valves from the earlier 1.6's...even have one here in the house from years ago. Although, I personally never had a problem with one in the old cars in almost 39 years of running them. Believe it or not.)

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No worries man, I have asked questions on others posts all the time. Thats that great thing about a forum. I will try the pressure relief valve thing and see what the outcome is. I have filled up with diesel from another station and it seems to be running way better with much better fuel mileage. The studder is still there occasionally but nothing like it was.

09wingates said:

I have filled up with diesel from another station and it seems to be running way better with much better fuel mileage. The studder is still there occasionally but nothing like it was.

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Water in the fuel?
When was the filter changed last?
Can you get a sample from the drain on the bottom?

Fuel filter X2, Air filter? Clogged intake manifold?

Fuel filter was changed about 10k ago. Air filter is a few months old. I havent ever looked at my intake manifold yet but I suspect its clogged some with the amount of miles on it. That a project I plan to tackle soon.

09wingates said:

Fuel filter was changed about 10k ago. Air filter is a few months old. I havent ever looked at my intake manifold yet but I suspect its clogged some with the amount of miles on it. That a project I plan to tackle soon.

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Pop the hose off with some large pliers and turn your cell flash / video camera on to record and check her out.