Idle speed drops

Hi everyone. i'm new to the club but have owned my mk1 gti 1.6 for about 9 years. recently trying to impove things!!
The car idles fine at around 1000 rpm hot/cold but when lights/ fan/ anyting is switched on the revs dip. has fairly new alternator and battery but is becoming a problem in the colder darker weather. Any ideas what to do would be great.

First this is what you might call normal for an engine without any kind of idle stabilization. If it is too extreme, as you seem to think, then first check the electrical items. Battery in good shape? All wires and connections good?

You can add one of the idle stab systems VW has ysed over the years but that would require some extra cost, not a lot, and adding things in the engine bay, not original and adds to clutter if that is a problem. You can also just turn the idle up a bit during the Winter and back down when it warms back up.

thanks for the reply. Have had a good check of electrics seams ok. going to get the idle and mixture set by someone who knows what they are doing today hopefully will help. Will look into fitting an idle stabalizer from a newer car. Any idea which car i should be getting it from to make things a bit easyer?

One system would be the one used on 1.8L 16V KR code engines. It consists of a control box, idle stabilizer valve, some tubing and a little bit of wiring. I have used them on 1.8L 8v engines in the past and it worked out very well. On a 1.6L it might allow a bit more air than needed and cause a slightly higher then 950RPM idle of a 1.8L.

A second system uses a solenoid type air valev, two for air conditioned cars, a relay and again some wiring and tubing. This system does not stabilize the idle as well but does work OK. There are many engines which use this one, mostly early CIS models and the parts should be cheaper and easy to locate.