Volkswagen Repair: cold start idle problem, mass air flow, high octane fuel

Question
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Followup To Question -
Thanks very much for the original info.  I am sure it will prove helpful, but I'm realizing I may have left out some additional, pertinent info.
1)The check engine light came on a little while after the park plugs were changed but before the wires and coil were replaced.  Since the final repair the check engine light has not come on.
2)The sound I hear now is more of a slight chug-a-lug (low to high) sound, and less like a low idle.  The sound also does not really occur when in park, usually only when in drive.
Thank you again very much.  I really appreciate.

Question -
Hi, I own a 2000 Golf GLS (87,500 miles).  I've been having idle problems with it for approx. 2 months or more.  It idles normal for a second(usually when cold started) and then the idle drops low and comes back up again, going back and forth erratically for a while.  First the spark plugs were changed.  The result was a slight change in the idle problem sound quality (sounded a bit more solid).  Then it had the wires and coil replaced because the problem was lasting longer and was also occurring sometimes when not cold started.  Now, the frequency and strength of the idle problem is minor (only occuring sometimes when cold started), but nonetheless, it still remains.  I also tried a fuel injector cleaning fluid in my tank.  Thanks in advance for any help you can offer!

Answer -
Alex, thank you for your question.  You could be having problems with the Idle stabilizer or the Mass Air Flow (MAF) sensor.  I would also check the condition of the air filter and make sure that it is clean.  
Hope that helps  

Answer
Alex, thank you for your question.  If you are getting the sound like it is dieseling (that can be compared to a chugging sound), then the problem is with the injectors could be getting dirty.  A good cleaning can be done by using a (yuck) high octane fuel like 92 octane (but painful on the wallet).  Chevron sells a fuel injector cleaner that is a fuel additive. It will also clean the injectors.  There is also a way of cleaning them off of the car but is usually much more expensive.
Hope that helps