forum.audiv8.com Foren English Audi V8 Forum Idle stab valve

Hi all.
Firstly, does anyone know the difference, other than part number, of the idle stab valve?
Early cars, PT?engine -->M chassis. 078133455A (last known price in UK, £180)
Later cars, PT and ABH M chassis--->. 077133455B (Current UK price, £400+)

are there any major electrical differences?
Interchangeable?

What is the price in the rest of Europe?

situation is-

Idle is very high. 2000-3000rpm. The stab valve has been replaced, but the problem remains.
A third ISV was tried, but no change.

All 3 stab valves working correctly on another car.
If the valve is disconnected, idle appears normal.

Are there any electrical issues likely to cause this?

If you allready checked the fault codes, than You need to check throttle valve potentiometer, it may be faulty or needs an adjustment, also check the throttle valve itself if flaps closes and opens freely without sticking.

There are no functional differences known regarding the ISVs. regarding your problem I'm with George.

Cheers guys.

Hopefully my New, Lago 4.2 will be through its MOT shortly, and I can bring it up to start getting it back to clean and tidy.

It needs some paint, and the front screen has to come out for som rust prevention. So sourcing windscreen trims is now critical on 2 of them.