on idle

[match]

it is single point i ran an injector cleaner through it (redex)

[AudiA8Quattro]

Is that single point injection as opposed to multi on a gti, how does that work then?

yes..


well its like a carb, but it has one injector that feeds all 4 cylinders unlike gti's that have one injector per cylinder.

Correct.
However everything is controlled by an ecu, that's where it differs from a carb.

[AudiA8Quattro]

A couple of suggestions.
Check for any vacuum leaks around the injector unit.
Also there is a throttle potentiometer with a built in idle switch on the injector unit.

[match]

thanks will have a look for splits and whats this switch?

[AudiA8Quattro]

Next to the where the throttle cable mounts is a 4 pin connector.
Disconnect it, put a multimeter set to resistance on the bottom 2 pins.
With the throttle slightly open it measure not more than 200 ohms.
With the throttle shut it should measure infinity.

[match]

and if not?

[match]

Next to the where the throttle cable mounts is a 4 pin connector.
Disconnect it, put a multimeter set to resistance on the bottom 2 pins.
With the throttle slightly open it measure not more than 200 ohms.
With the throttle shut it should measure infinity.

I dont suppose you have a diagram?

[AudiA8Quattro]

A feeler gauge is used to test the switch in this diagram.

[match]

how about this mate
idle stabelizer valve on the front of spi unit
do you know anything about this?

[ace]

if it has an isv, i would try cleaning it out and seeing if that makes a difference