Mk2 Golf erratic idle and running rich

[Volkswag]

So I've had my Mk2 Golf GTI 8v for a while now and I've fixed a lot of problems, but there are a few that I have been unable to fix. The idle is extremely unstable when first started and will vary from 750rpm to about 1250rpm and almost stall. After it has been running for a while it settles down until you start driving and stop again and then the same happens. The second problem is that the car is running rich, from what I've worked out running about 12L/100km or more. I have had the AFM and spark plug leads replaced, as well as the blue coolant temp sensor and although this has increased the cars performance greatly, these two problems are still present.

I don't know a whole lot about cars and I am unsure of weather these things are related but I really want to get it fixed as soon as possible because I can barely afford the fuel, so I was wondering If anyone has had the same problems and knows what it could be?

Thanks

[golfmeup]

I'm no expert, but it sounds like an correct mix of fuel and air.
A leaking vacuum system? Possibly a faulty idle stabilizer valve.
I'm sure someone else will chime in with their thoughts.

[h100vw]

I'm no expert, but it sounds like an correct mix of fuel and air.
A leaking vacuum system? Possibly a faulty idle stabilizer valve.
I'm sure someone else will chime in with their thoughts.

Base idle needs setting along with a basic setup of the car in general. If that isn't successful, then check for air leaks.

Gavin

[Jarred]

Hunting idle is common issue. Clean out the ISV, then set up the idle from scratch.
This info has already been convered on the site, do some searching. I believe it was Velly was one who posted some good info.

[Alex Mckenzie]

Not sure if this is covered on watercooled but check out this site. Although do the timing before setting the co.

GolfGTIforum.co.uk - An independent forum for Volkswagen Golf GTI enthusiasts.

[blis]

Not an 8V owner ISV's might be triggered by an IDLE switch, it could be dirty, frayed etc. I agree with gavin too, base idle is a good place to start

PS: RJ is a living legend!

[benough]

^ This guy. Solved 9 months of hunting for a solution when this frayed plug was discovered.