2001 1.6 Golf Erratic Idle

Sorry I'm not able to help you directly, but it might help others to help you if you posted what the garages had done to try to cure the problem?

Chris

As Chris says; tell us what else they've tried. That written if you can isolate the switch and remove it, then see what the idle is like, if there's a change then they (you) may be on to something.

In general terms, the power steering switch increases the idle speed when you move the steering wheel, because the power assisted steering draws power from the engine and otherwise it would struggle / labour / stall. If the switch is flicking on and off this could cause the idle speed to seemingly move from the ordinary idle to a faster idle.

Erratic idles on non FSI Petrol VW's are almost always caused by a knackered EGR valve and / or coked throttle body which needs cleaning, and then re-aligning.

Tim..

Garage (Not Volkswagen) told me that they changed air filter and checked manifold for leaks.

I wonder if it's a split hose ?

I know the throttle body on these cars can get really mucky so my first port of call would be to get some throttle body cleaner (carb cleaner) and give it a good clean especially around the edge of the butterfly where the grime can cause it to stick causing eratic idle.

Try cleaning the throttle body with carb cleaner. Another possible is the engine coolant temp sensor, a very common fault. Replace with the uprated "green" one.